Additional options for Alliance Diplomacy

Yeah thats a must have. I was about to take a juicy system when the sophons accepted a truce. 

I definitely agree with this. I just played a game where I played as Sophons allied with Cravers, Unfallen, and Lumeris and every 20-30 turns or so I would end up at war for no apparent reason (though I assume the Cravers had something to do with it usually). Also just as unnerving, often times as the war was starting to get interesting, someone out of the blue declared a truce, so often I would end up cancelling invasions on the verge of victory. 

I wish I knew who was declaring war and truces on behalf of the whole alliance and that there could be some say that each member may have to approve or disapprove of such actions for better or worse. I definitely think it will improve the alliance system and make it seem more organic in my opinion. 

Also I would like to see if it is possible to reprimand an alliance member that persistently pits the alliance into conflict either by imposing some sanctions or kicking them from the alliance, by a vote of course.

While on the topic of alliances, is there any particular reason that the limit on alligned civilizations is four (the game I played had eight civilizations)? I ask because I was able to end up on good terms with all the civilizations in this play through (when not at war that is) and often had civilizations ask to join an alliance even though that was mechanically impossible given the afformentioned limit. Perhaps this could be balanced by making it harder to improve relations with civilizations to the point they consider an alliance so that it is not possible to get on everyone's good side or at least very difficult.

I really agree.

I agree! I'd also like to be able to veto or influence other members of my alliance inviting new members. I hate it when I get the weakest player in the game suddenly joining my alliance because another member thought it would be a good idea, and not being able to kick them out again.

Similarly, I'd like a way to influence alliance members working together towards a common goal. Generally I've not been in a situation where my allies are working towards the same victory condition as me. I've found myself in a situation a number of times where I've satisfied victory conditions for wonder/science/conquest/etc and my allies aren't doing the same thing. So, either I have to build enough wonders for everyone (can't do that with a science victory, though) or leave the alliance and win on the next turn.