Was difficulty nerfed in general?

Maybe we have just become better players overall

So for the difficulty difference ME1 was a cake walk. You really felt the changes there.

ME2 was easier in a lot of places but Horizon and the Reaper IFF mission were still very hard. Horizon is hard because you need to micro manage a bit more towards the end than you do for most of the game. It also is a fight that benefits having a lot of biotics which you don't have at that point(samara and thane). The reaper IFF has the one part where husks are swarming you on top of them shockwaves from the scions. That part is brutal. Plus the end of that mission but I found the trick was playing CoD zombies with the husks. In general I think that the difficulty change was more due to knowledge and a change because of RP. I like adept in me1 and 3 but on ME2 I know it's underwhelming on insanity so I went sentinel and OH BOY was that a good decision. Now couple that with my newly found appreciation for biotics in certain situations things naturally got easier.

ME3 was about the same as og. I have to say IDK if enemy fire rate and accuracy is based off of FPS though. I know og ME3 was much easier on consoles with 30fps than on pc (boy was that a shock when I swapped to pc). So yeah Garrus is still op and ME3 gold solos really make you good at single player.

In the reaper iff, I use miranda and thane, because bothers have warp, to strip down armor. My extra femshep power is barrier, to gain a little extra protection, and to allow me to spam adrenaline rush so I can take down enemies that get too close, or eliminate harbinger in one go when needed (barrier's long duration allows for use together with AR, and it might not be possible with a purely offensive power").

As I mentioned on the OP, this is the one mission I restarted to optimize the team; well, my "non optional" (imho) were, exactly, miranda and mordin. The reason I think thane is a better option on that mission is because the warp power does a great job of stripping armor away, and thane has weapons that can handle long and medium range encounters, while mordin's guns are better for close range, in a mission you don't want foes getting close. Also, you will have "throw" for crowd control, for an effect similar to the one you use crio blast for...

Gotta say that an even better composition might be loyal samara (so you can have reave for armor damage) and thane for his warp, because tech powers (like Miranda's overload) are kinda wasted on that mission. With samara and thane you'd have warp and reave for armor melting, and two instances of throw plus an instance of pull for crowd control (though if you are going to take the trouble of making them loyal, miranda can also help with CC as she'll have slam, so maybe not such change after all...).

Anyway, for a soldier, I think any combination of thane, miranda (preferably loyal) and samara (loyal) are great for the reaper Iff...

I also take the black widow, simply because I don't think the revenant is better than the mattock in Me2. Its volley spreads too much and many shots are lost. So it was also one of my optimizations, to keep the mattocks and upgrade my sniper. I noticed that the number of times I managed to finish the first wave of collectors before harbinger coukd show up increased with the mattocks in comparison with the revenant...

Ffinally, bring the cain, and save your shot for the scion. You'll simultaneously take more than half its armor and the first wave of husks that would try to pressure you, and it makes it a lot of easier to keep covered and protected while keeping collectors at bay from long range to chip away at the scion...

Oh, also, I used to pick the revenant, because as a soldier, the assault rifle is my bread and butter. But testing performance, effectively, for me, it is no great upgrade compared to the mattock. Really, having to make controlled bursts to contain the spread made it slower than the mattock in middle range, and far worse in mediun-to-long range.

But indeed, if you get in medium to close, or close range, the revenant dominates, being faster than the heavy pistol or shotgun to strip armor. It's just that as I try to prevent that scenario in the first place,and I have the shotgun and heavy pistol already for closer encounters, I currently feel the mattock gives more versatility as it dominates medium range...

Sure, by no means i intend to mean my tactics are better. Its just that someone explained theirs, and I explained mine; what sorts of strenghs I'm harnessing, and the kinds of weaknesses I'm exploiting...

As I said, I just started an adept run on ME1. There is a very large chance I'll switch my ammo to cryo in ME2 this time, just to figure out if there are options i've been overlooking. Eventually i'll try the bonus types, specially warp, that is reputed to be OP.

That said, obviously, the window of viable strategies is smaller on insanity than in lesser difficulties, because you need to optimize and sinergize more as to not be overwhelmed, and because enemies tend to gain new layers of protection that are otherwise missing. Jack is one I feel suffers a lot, due to the sheer number of enemies that gain armor...