Least Favorite Class

Soldier.
If I just want to shoot I'll play Gears of War.

Sentinel

Of all the playthroughs I've completed, not one of them was as a sentinel.

I remember seeing you post in a thread here that you've beaten each game in the OT more than 200 times, so this is really impressive lol

Yeah. I might've remembered the cumulative number instead. Still impressive.

I always like to rag on hipsters who say Soldier is their least favourite just because it has the most emphasis on gunplay. (Hey, hipsters! Infiltrator is the second most used class by the playerbase! Gonna rag on that one too?) I've played enough Mass Effect and Gears of War to point out how their cover shooting mechanics are quite different. Hell, I got into Mass Effect based on it being Gears of War IN SPACE but also an RPG and having a tank you can get in and out of like Halo. (Somewhat false advertising, but I do love the Mako) I didn't even recognise BioWare at the time, and thought Mass Effect was a AA or even just A game.

That said, the classes play quite differently from game-to-game. ME1OE, ME1LE, ME2, ME3OE, ME3LE, and ME3MP all have different dynamics (the differences between ME3 OE and LE being merely that LE forgot the bloody patches - and for the sake of simplicity, I'll only use the Alliance Marines for MP) and in ME1OE, Soldier is fairly redundant compared to Infiltrator unless you really like assault rifles and shotguns. With LE tweaking Immunity into a short-burst defensive option, I assume Adrenaline Rush becomes more useful - but Infiltrator becomes a bit better with ARs and shotties. The big loser though for me is Sentinel. In OE it has no weapon options at all aside from getting Marksman via the passive, and clicking powers constantly is boring without some basic attacks to bread my butter. Maybe in LE it's better, but I really don't like LE.

Sentinel becomes actually somewhat fun in ME2, but a big sturdy boy like that really should have had assault rifles. Just assault rifles and heavy weapons. Nothing else. The "I'm a squishy caster!" sidearm duology works for Engineer and Adept, but Sentinel is a knight in shining armour. Tech Armour (nerfed somewhat - make it work like ME3 Defence Matrix minus the cooldown penalty or something) is your shield, your assault rifle your sword, your heavy weapon your halberd, and your powers are your horse. As is, I still don't like Sentinel much. Too much survivability, too little damage. Boring. Soldier comes into its own here though, almost as good as Infiltrator. Infiltrator clicks on heads, shoots fire at specific problem targets like flamethrower guys, and can turn invisible. Soldier activates Spartan Time, becomes Master Chief In The Books, and melts everyone with a hail of superhumanly fast semiautomatic fire. They both have just enough survivability to make taking risks viable, and unlike Sentinel, they're not braindead about it.

ME3 is where Vanguard becomes the tankiest class, but not in a braindead way - you have to keep chaining Charges in order to dish out damage with Novas rather than just constantly cancelling them until God Garrus eventually gets shot/your team kick you after the match for scoring 50 points. Alliance Vanguards don't need to bother with Shockwave. Maybe three points for team support alone. Vanguard Shepard doesn't need to bother with anything else, but can if he wants. I recommend charge-fire weapons you can unleash while Charging or Novaing, or automatics you can fire in spurts in-between powers for both Alliance and Shepard. Just watch your Charge cooldowns. Infiltrator loses survivability owing to improved AI, but gains in sheer power thanks to everything else about Tactical Cloak. Cryo Blast sucks arse on the Alliance Infiltrator compared to other possible options, but still provides solid team support against enemy armour. Shepard can run with Dominate, and bypass its long cooldowns by using Cloak beforehand. Sticky grenades are unique in that they carry your ammo power rather than having elemental properties of their own. They also detonate fire, lightning, and cryo primers, including their own. They inexplicably do half damage if thrown while you're carrying a sniper rifle however - unless you ADS.

Sentinel? Sentinel is still boring. Hate to break it to you Shepard, but your base 500 shields isn't good enough to really be bulky, even if you stack bonuses like they're going out of style and double up on DR-increasing buffs. You're not good enough at being bulky to use a bulk-heavy playstyle that can ignore cover even in bursts. (If Wrex were to give up those damn stimpacks on the other hand... you suck quads with them! Let me have them dammit!) The Alliance Sentinel is even worse somehow. Just play as the damn asari, she can hard counter Phantoms. I'm not asking for Jugg-level toughness, because that's like a Blissey with 300 Defence and Speed by campaign standards. (In MP Juggy is just a regular Eviolite Chansey) Just a reasonable Swampert level of bulk where you can take a solid number of hits without completely crippling your cooldowns.

Soldier Shepard is the same as ME2, but now with explosives! Frag grenades may be basic, but they get the job done, and everyone underestimates them. They detonate tech combos too, as does Concussive Shot. The Alliance Soldier is much the same. Adrenaline, frags, concs. Prime combos with fire or lightning bullets, detonate them with the Morshu Special or a high-impact strike. Simple but effective. The BF3 variant having Carnage isn't as useful as you'd think, owing to longer cooldowns. The BF3 Infiltrator's Incinerate would have been a staple, though. A pity she went unused.

Soldier. I've played the OT many times and Soldier and Infiltrator are the only two classes I haven't done yet. I just finished my Vanguard insanity run - ended up enjoying that classes playstyle more than I thought - even if I was OP in ME3. I'm going to do Infiltrator next - Soldier just seems too boring without tech or biotics to me.

All opinions expressed are entirely subjective.

I generally do not like how any of the ME games handle point allocation. ME1 and ME2 require you to spend points on some talents to unlock other talents (Shockwave into Pull to use the example you provided.) I believe ME3 locks talents behind your level, but you will not notice it on an import.

That being said: locking some your talents does reduce choice indecision with new players, so I can agree with that idea on some base level. However, more experienced players like us would prefer to get some other talents sooner, or just skip the talent we do not want. Removing talent unlock requirements would increase build variety.

Now I will disagree somewhat with your opinion on Vanguard and Soldier.

For Vanguards specifically, Cryo Ammo and Pull/Shockwave do not work well together. If you want to be more of a caster Vanguard, then you will not be using Cryo Ammo anyway. If you are a charge-focused Vanguard, then you will not be using Shockwave or Pull (although having Pull before Shockwave would be nice).

Soldier also does not really suffer at all from their talent schemes:
- First two missions (Lazarus Station and Freedom's Progress) are against mechs, and Disruptor Ammo rank 2 adds synthetic stun as crowd control. You start rank 1 Disruptor Ammo in Lazarus Station, and can level up and get rank 2 before Freedom's Progress.
- After the first two missions you should recruit Mordin to unlock the research terminal. This mission is mainly Vorcha and Krogan. Incendiary Ammo will stop Vorcha and Krogan health regeneration. You can get Incendiary Ammo by level 3 which will be at a minimum after completing the first two missions.

I suppose if you want Cryo Ammo on Soldier earlier, then I can understand that to some degree, although Disruptor Ammo rank 3 can also overheat enemy weapons and Squad Disruptor Ammo gives that to all squadmates when they use it. That weapon overheat will debuff the enemy so it helps reduce damage to Shepard even if it is not as obvious as cryo ammo's crowd control.

And Concussive Shot has a 6-second cooldown (with no possible cooldown bonuses) so it simply is not attractive enough to use. You can very easily ignore it.