Manveer Heir speaks out against EA

But you don't need any of those to get the full story. The base game already gives you the full complete story, while the DLCs just add to it. 
To address each DLC you mentioned:
Helping Liara become the Shadow Broker adds nothing to the story since she becomes it with or without you, the only difference being Shepard not knowing she is until it is revealed. 
Leviathan is not important to understand the story since he just tells you what the Catalyst does later, only from a different perspective which adds to a complete story. 
You don't need Witch Hunt since you can already learn about Eluvians if you play the Dalish Origin but also by the time they become relevant in future games they are explained by Merrill and Morrigan. 
As I said, Legacy is really the only exception to this but it is a DLC for DA2 and it adds nothing to that game which already has a complete story. 
As for Trespasser, not really since we learn Solas is the Dread Wolf in the cutscene at the end of the main game between him and Flemeth/Mythal.

All of these things do not complete the game they were created for, which are already complete by themselves, but merely add to the games they are for. 

and Arrival DLC. Javik. MEA left half the questions unanswered.

Seriously, defense force here is something else. 

Good news is that he’s a HR and PR nightmare.

Also he didn’t share anything we didn’t know about the Hydra that is Electronic Arts and their practices of ruining development studios.

The DLC's you mentioned are all peripheral to the main story of which they're attached.  

The main story of "Mass Effect 2" was stopping the Collectors all while experiencing the personal stories of your new crew.  Liara in ME2 had a minor presence in the story and chasing/defeating the Shadow Broker was peripheral and, ultimately, not essential.  Now, if you want a completionist view of the Mass Effect Universe and how Shepard's body was recovered by Cerberus, it's a great story and, as it turned out, one of best DLCs BioWare ever created for their games but, if you never played it, you only miss minor references in ME3.

"Leviathan" was interesting lore and it would have been nice if it had been included form the beginning but I don't know if hurt or helped the "Reaper" mythos.  Personally, I felt "From Ashes" being cut out and sold as a day 1 DLC was a more egregious issue.

"Witch Hunt", was an epilogue DLC.  While it ties in the events of DA:O, you won't be lost in the DA universe if you've never played it as eluvians are mentioned in DA2 and DA:I.

"Legacy" was more of a "bridge" DLC to DA:I and not connected to the main story so I don't how you'd include it in Hawke's rise in Kirkwall.  Additionally, you learn all about Corypheus through the codex, dialogue, books, etc in terms of how he fits in the creation of "the Blight" in DA:I.

"Trespasser" was another "epilogue" DLC that occurred 2 years after the events of DA:I.  Again, a great DLC but, while it added to the overall narrative arc of the game, you got a full game from the Inquisitor being interrogated by Cassandra to Corypheus' defeat without.

It's like editing in a movie - ultimately, there is a story to tell and you have to decide what is the best way to tell with a limited amount of time and resources before it needs to be released.  Most of the DLCs I have heard were considered in peer review as being included in the main game during one point or another but didn't have time to be developed before release but were compelling enough to explore later on.  "Bringing Down the Sky", "Overlord", "Arrival", "Mark of Assassin", "Omega", "Jaws of Hakkon", "Descent" - all fun and worthy DLCs but I can't point to one in which the main story suffered for it's exclusion.

From my experience and memory (I started gaming in the late 90s), expansions were more commons in the 90s to about mid-2000s or instead of an expac, you had a sequel released in like 1 year to 1.5 year. Sometimes you had both like Baldur's Gate to Throne of Bhaal (2 full games + 2 expac) releasing over 3.5 years (December 1998 to June 2001). The Wing Commander series went from 1990 to 1997 with 5 full games, 5 spin-off and about as many expansions. NWN and NWN2 also had quite a bit too but NWN2 was pretty much the end of content expansions as huge content updates.

It really depends what kinda of genre you have been playing I think, because today, outside of BioWare games (which always had post release content outside of Jade Empire which was a financial flop, KoTOR which got a sequel super fast and the Sonic game everyone pretend they didn't made...MEA had MP DlCs) nobody else really do post release content on the RPG market (minus The Witcher 3 and Pillars of Eternity but POE was meant to be like BG1 in regard to that).

The large expansion->small DLCs shift pretty much match with the release of the Xbox 360 (2005). It came with a size download limit for patches and DLCs imposed by Microsoft (2GB if I remember properly, Lair of the Shadow Broker is pretty much the max from what I remember). Then you add that DLCs became a marketing tool in the last few years and that making an armor reskin and selling it for $10 has a bigger ROI than a $20 expansion that takes a year to make and you got the cluster we got now...

Lets not talk about sequels, they are now 3 to 5 years later for successful games unless you are one of the Big Ones (COD/Battlefield/Sport games and these kinda cheat by having more than one game in development at the same time). Even MMORPGs have issue releasing sizeable expansion these days.

How is Leviathan important to understand the ending? And yes, the original endings do have the Catalyst talk about its origin as well as the questions about the Reapers. 
Morrigan talks about it in Trespasser when it becomes relevant, meanwhile what does it add to Dragon Age: Origins, the game it is a DLC for? Requiring the player to read the books is a separate issue, and one I agree with you about. Luckily it seems Bioware learned that lesson since MEA didn't do that, and instead while the book expanded on events the game gives you all the info you need. 
You'd learn all of that about Solas in DA4 when it is relevant. Nothing was incomplete in Inquisition that Trespasser completed. Though I agree they shouldn't have left Trespasser as a cliffhanger(if you meant the base game ended with a cliffhanger, I disagree entirely), especially if the Inquisitor isn't going to be the protagonist in DA4. If they do that, it ruined an otherwise great game with a complete, full story. 

I don't have a problem with it.  They can't put everything in so I don't mind if they release SP DLC post-release/between games as long as it's not you paying for an ending.  I don't even mind if BioWare rewards new game purchase versus used game purchase with DLC like the Cerberus Network which was not extra cost apart from the initial release.  I do have an issue, however, with them cutting entire sections of content essential to a main story like "From Ashes".   I bought the Collector's Edition so it wasn't necessarily an issue but I couldn't imagine playing ME3 without Javik.  This wasn't a "one-mission plus static character on the Normandy" DLC like Kasumi...there were a ton of dialogue and cinematics that tied directly with the previous cycles experience with the Reapers.  

DA:I ended the way it did because they are looking to produce another game so, yeah, cliffhanger.  Within the game you had a full story, from beginning to end, and a final scene between Solas and Flemeth.  

Well, I do. DLCs are supposed to be stories separated from the main story. Call me Witcher fanboy, but TW3 handed it perfectly. So perfectly, in fact, that their DLC was chosen as RPG of the year. A DLC! But with Bioware, even if you don't read the books/comics you may be confused with the story and characters. I also agree about Javik.

And about the cliffhanger: it wasn't a cliffhanger to DA4, it was a cliffhanger to Trespasser! Trespasser answered all the questions I had: Solas' motivations, if he really was a god, his objectives, etc. There are no more questions to DA4, so there is no Cliffhanger. Also, they added an ending to the Inquisition, which I think at least SHOULD be important in later games, since the Inquisition was probably the most powerful order in Thedas at the time. 
I imagine people opening DA4 codex and are like: What the hell, what do you mean the Inquisition got dissolved? When did that happen?!

There isn't anything here that we didn't already know about EA for Christ's sake. No news flash here my dude.

Who cares what that supreme racist "curry thunder" says? Dude is a walking cesspit. Just another one of those "power + privilege" whiners that blames there own shortcomings on everything but themselves. Fuck him.

Also, lets not give DongYea anymore YT ad revenue, kthxbai.

Were people confused when DA2 started with a new protagonist and location?  "What's this?!  This isn't my hero? Aren't we going back to Lothering?  What about Redcliffe?  What's my name again?   (arms flailing around)"  Were people confused when they started another game with, again, a new protagonist and location? "First, Hero of Ferelden and now Hawke?  What sorcery is this?  What is an 'Inquisitor'?  I'm cold and wolves are after me".

People will be fine... 

DA4 is going to be about Solas, that was conveyed through the ending available in DA:I without "Trespasser".  The new protagonist in DA4 is going to be uncovering information about Solas and his motivations 

I don't check you on the first two. Morrigan and Varric tell the Inquisitor everything the Inquisitor needs to know about those things.

Trespasser, sure. But I don't see how it's conceptually possible for a post-ending DLC to avoid telling the player things about the future of the game-world which he otherwise wouldn't know. Unless we want to make it a rule that post-ending DLCs have to be pointless and irrelevant, but I don't want to go there.

Yong Yea ... that's not that one Gamergate douchebag who thinks the Nazis were socialists? No, that was Ian Miles Cheong.