I've only played till Priority : The Citadel II thus far, but honestly, the new squadmates have been pretty lack-lustre.
Part of the problem is that they don't mesh with the... chemistry of the game events well, imo.
Spoiler for up till Tuchanka:
In a series of missions that were strongly intertwined with Turians, ME1-old comrade bonds, Krogans, genophage, etc...
Why the heck would I bring anyone else other than Garrus/Liara for maximum chemistry? It 'felt right' to bring them along in a personal mission that they had seen through since ME1, the dialogues felt right, 'they' felt right.
Even the Rachni one. Sure, Liara didn't have any interesting dialogue, but it felt right having her given that her mom was part of the events leading to it. Garrus/Grunt/Shepard for bro-someness.
The only one I've regretted a little bit thus far is that I chose not to wait for Kaidan to bloody rejoin me and went ahead to grab Javik. Otherwise, Kaidan/Liara would had been the perfect duo. But it was okay.
I may be wrong since geth hasn't come into the equation, but I don't see the need for EDI to get a body aside from letting Joker harden his bones only to break it. Sure, there's some development on her developing personality coming from a human-ish touch, but aside from that... nothing yet.
And James? His story ended just as soon as it started. Mind you, I have nothing against Vega and I find him to be decently funny, but it wasn't worth a squadmate slot. I'd much rather Anderson be the squadmate, but alas, plot.