I replayed parts of all three games in the leadup to MEA, and I think that, for me at least, 2 is the one that's aged the worst. Plotline wise, we've got the entire Cerberus thing painfully destroying the illusion of choice, and the Council becoming even dumber than the original game is just plain infuriating. And Liara the cold-blooded information broker still makes no sense. Also the Virmire Survivor being a massive ass.
Gameplay, even with world-building extensions like Omega and Illium, reducing all the missions to cover based straight paths honestly made it feel a lot smaller to me. And if they wanted an ammo system, they needed to make it work a lot better. Way too much running out of ammo in the middle of a fight for no damn reason.
And the Hammerhead is the worst vehicle in all the Mass Effect games, coming in well behind Lair of the Shadow Brokers taxi.
Matrix Dragon, J. Random Nutter