EDIT - Oh, and what you said about James...I was guilty of picking the other guys over him, but I really need to focus on taking him to more missions. I remember someone saying he had great dialogue but ppl usually assume he's just a stand-in extra, however he's pretty great and you should give him a chance. I must remember to take him to the Academy with me when I do a Jack-less run.
I did it because there's nothing on the surface that makes me want to dig deeper. Remember the phrase "you can't judge a book by it's cover"? Well, that's wrong. Humans do it all the time. A cover is what draws you to a book to decide if you want to take the time to check out what is inside.
When we first meet James, Shepard knows him so he isn't introduced to the player at all then is immediately pushed out of the events of the scene by Anderson only to pop back in so the Virmire Survivor can deliver a stupid, cliche line. The next time he speaks he's whining like a small child and I love telling him to shut up. Then if I do care to talk to him ever again for some weird reason, he's an *******. At least I get to kick his ass.
For me I find the geth dreadnought mission is better having Tali dead in ME3. Admiral Xen has some good dialogue
If Mordin is dead, Padok Wiks replaces him. Good character. I've read posts from folks saying they prefer him over Mordin
If Jacob is dead, Dr. Webber takes his place. Everything is nearly the same except Dr Cole, voiced by Jo Wyatt, gets more dialogue
In regards to doing Grissom without having Jack in the game. I agree the mission isn't bad without her, but my issue is with the squadmates. Without Jack, Ensign Prangley will be killed. Had the squadmates provided cover fire for Shepard while helping get Rodriquez to the shuttle, Prangley most likely would live
If Grunt isn't in the game, Urdnot Dagg fills in. He's another good character. Too bad he dies.
Admiral Xen is awesome, in no small part because of Claudia Black's voice, but she also should have been more important. Remember, she wanted to Control the Geth back in ME2. Had they kept that idea relevant, the Quarian conflict and the three Admirals would have set up the endings. You had Garrel for Destroy, Korus for Synthesis (makes more sense if he met Legion), and now Xen for Control. Raan is the mediator.
As for the squad mates, I don't see how anything can be worse than Shepard not doing anything while Thane fights Kai Leng. That's even worse than Kirrahee just standing there and taking the shot or Thane jumping on Leng's sword.
I like Dagg too. I wish they gave him the full Grunt fight, all the way to charging off the cliff. I don't need to see either get chopped up to understand that they died. If they don't come out at the end, I get it.