Shep & Tali not being an option is definitely a travesty. I think there's even a point where you can flirt with Tali but she just gets embarassed. Not sure if I'm remembering that right though.
Yeah, I was pretty miffed at not being able to romance Tali with Shepard (There's a male shepard ? Naaaaah !). She's my favorite character out there. And she kind of do some sort of confession in ME2, after her loyalty mission,
mentioning how linking two envirosuits is the highest show of trust between two people among her people and how the only one she trust that much is Shepard, who then tease her about blushing. It really got my hopes up, but it was never followed through...
Well, ME3 has Traynor, who was waaaaay better than Kelly as com officer. She was kind of awesome in the Citadel's storyline and follow-up interactions. XD
One thing that always surprised me is that Jack is not an option for Shepard when she does mention being bisexual during ME2, when asked about her past. Well, she's not my type, so don't care much, but felt a bit weird.