I'd like to be able to offer everything the UP can declare to my allies. For instance, I'd like to offer the use of my starbases in trading to my close allies, and I'd like to demand they pay me for starbases/colonies in my influence. Particularly when there is a very strong alliance, it's a shame you have to wait for the basically random UP to throw up the right thing, and it'd be much better if you could just offer (and of course take away) the use of starbases or taxation in trade with individual groups. I usually have heaps of money, and perhaps offering to pay tax on your border-violating bases and colonies could ease diplomatic tension.
I'd like to 'declare' the way the AI can, by saying 'I hate the Dregin' or 'help me I'm getting slaughtered'. It'd give the player a way to sound out the AI leaders in a way that isn't currently possible. It would also make fighting proxy wars (which is great fun) much easier, by gently nudging other groups into war through inflammatory statements or promises of support.
Does anyone else have ideas for new trade options they'd like to see?