- Cleavage/impractical suits - Samara, Miranda, (teacher) Jack, to a lesser extent Benezia.
- Suicidal breather masks - going into a vacuum without anything to cover your eyes, ears, butt and/or other bodily openings will get you killed.
- Armour not being "armoury" - we all understand that a game needs to have a unique feeling, but spandex, latex or leather, these things do not protect against bullets, fire, ice.
I agree 100% with all of this. I enjoyed ME2 very much, but these types of changes drove me crazy. I hated that part of the game. They were very lowest-common-denominator and I hated it. If Miranda wants to wear her skintight bodysuit uniform on board the Normandy or on her shore leave or whatever, that's up to her, but on a mission there's absolutely no excuse for not wearing a hardsuit. In fact, it's plain irresponsible. The same goes for Jacob, and what's even worse about him is that he was in the Alliance. Of all the people who should appreciate the need and benefit of a hardsuit, it would be him. And don't even get me started on Jack fighting in harsh conditions of somewhere like Tuchanka or the Derelict Reaper while wearing nothing but a pair of suspenders.
And there's a particularly glaring logistical problem with not wearing a hardsuit as well: where do the power cells for things like their shields go? I know the cells have to be portable, but they have to take up at least some kind of space. Let's assume they're fairly small and say they're roughly the size of something like a portable desktop external hard drive or something similar. It's not that big and doesn't take up that much space, but it still has to go somewhere, and it's too big to simply go in a hip pocket. In the hardsuit, it's integrated into the design and wired for easy replacement, and its location on the suit is presumably in a place where it won't be in the way and where the weight of it won't throw off the wearer's balance. And then there are additional power cells to provide power to other possible suit functions, like life-support functions, and if they happen to have any kind of servo-assist or things like that. Completely sidestepping the fact that forgoing a hardsuit means forgoing the ballistic protection and life-support they provide, and any strength-augmenting servo assist they may also provide, but you have no place to store anything, including the power cells for the shields that you absolutely can't survive without.
And the breather thing is just dumb, no two ways about it.
Everyone in ME1 wore a hardsuit, and they did so for a number of very good and inescapably practical reasons. Taking that away after ME2 was a mistake in my eyes. The fact that they didn't do this kind of stuff in ME1 is one of the many things that made me like it so much. They wisely avoided the stupid 'impractical combat catsuit' cliché and I loved that. Then ME2 came along and they completely undid all that.
Then there's Liara apparently getting breast augmentation surgery at some point in the two years Shepard was dead.