I wish you had the option of talking to your party on the "hub worlds" like you did in ME 1. You got some great comments that way. Te team also needs to talk to each other more in hub worlds. Less "adds" or NPC conversations, more party interaction.
I also firmly believe that each party member should have 6 dialogue "trees". Like so:
1.) Post story mission comments - each party member should have something unique to say after each primary mission is concluded. This should have 1-2 "branches" (so it continues past a single comment, and then be done. (the branches should allow for paragon/renegade options that adjust your party members paragon/renegade standing).
2.) Default Conversation - Should be handled like Kasumi and Zaeed. The party member gives 2-3 comments about random events in the ship or other party members. This would make the ship feel more organic and alive, since it implies that the party is interacting and using the ship like real people.
3.) Personal History - This should have 3-4 branches so you can either recap their history with you, learn their story (new people), or get a sense of how they are as a character. each "branch" of the dialogue wheel should open after you take them with you on a mission (primary or secondary). Should also contain an option (after successfully selecting the correct dialogue) to open dialogue 6.
4.) Post personal Mission - should be a 1-2 branch conversation about the party members personal mission - the after mission dialogues in ME 2 are perfect examples (and well done) of how to do this right. Should also have an option to start/continue dialogue 6.
5.) Post game/Epilogue conversation - should be a lengthy conversation(1-2 "branches", lots of "investigate" options) about what the party member will do now that it is over.
6.) Romance Dialogue - once "unlocked", should be set up as 2-3 conversations, much like the ME2 dialogues. However, since it must be deliberately chosen, there will not be any "accidental" romances. Also, it can also have different "triggers" and, as it is separate from the standard dialogue, does not preclude you becoming friends with possible LI's instead of just shutting them down.
How would all of this work? Let's take Tali as an example for ME3, using hypothetical situation that she left the Normandy on Shepard's orders to make the to get the fleet ready to deal with the Geth.
1.) Since her first "mission" dialogue is after the events when you get her back, it is the reunion conversation. If she is a romance option, it is referenced and will be available as a dialogue wheel under (3).
2.) Back in her rightful domain in engineering, she would comment about the Normandy's engine, Gabby and Ken, Jack, Garrus and you most frequently.
3.) Catching up on what happened after the collectors (comments on your romance in ME2?) and why she left the Normandy temporarily. Some more information about the flotilla, most likely. Will also allow you to rekindle or end the relationship from ME2.
4.) After resolving the Quarian/Geth issue, you get some dialogue concerning her opinion on how you resolved it.
5. And the game is done! Now you get the conversations about Rannoc (if you resolved it that way with the geth), and what the two of you will do now.
6.) If this is a continuation of ME2, then only the first dialogue would be in engineering. Te rest of the dialogue's would start after the option, "Let's continue this in our cabin". She would also have a new set of "standard" kasumi/zaeed dialogue styles as she comments on the decorations. Depending on how you progress the dialogue here will determine the epilogue.
Now, if Bioware did it like this, it would be damn near perfect IMO. I can hope, but I am not expecting this level of excellence.