Assuming patches remain in the future for this game and not just the past, I humbly suggest that this game could gain a ton of strategic depth if diplomacy (the research tree and in game function, not the expansion) was made viable in MP again. 

I do not believe that this is ever going to be possible by simply offering "stat boosts" thru pacts.  These end up either being too minimal to be worth the fleet support and research costs, or so OP they damage the balance of the game with their existance (old TEC supply pact I'm looking at you). 

I think the way to truly make the game more dynamic would be to devise some "crossover" techs that blend strengths of the two sharing sides to unlock new abilities or possibly even ship types. 

A couple of examples:

"Massive Drive Engine tech" between vasari and either other race that allows the non-vasari player starbases to move within a grav well while increasing the speed of the vasari SB (perhaps also make this use an upgrade slot)

"Phasic torpedos" between vasari and TEC that grants orgovs' torpedos the same level of phase bypass that the vasari currently has, while granting a strong anti-structure torpedo attack to vasari cap ships (or unlocks a vasari anti structure ship)

I can also imagine several advent crossovers that could make culture much more revelant.  The idea is to make pursuing diplomacy for the very nice techs a path to victory at least equivilant to a pure military or economic approach.

This may be a better "sins 2" discussion since I'm suggesting a complete overhaul of the diplomacy tree, new ships, abilities, etc, but I'd like to see this game only get better.