I suggest that the initial game settings should have different research rate settings for each "tree" instead of one global research rate setting.

The variable research rate setting was fun in GalCiv II.  However, I feel that even more variation on gameplay can be achieved if the research rate for each type of research is varied.  For example, if colonization technology researches very slow compared to other technologies, then we would see a game with fewer good/colonizable planets and the fewer good ones swing the game more.  Or if the engineering technology can be researched really fast, then we have a type of game where we have more mid game type of diplomacy (as every faction explores and meets every faction faster), but with colonization and warfare technologies lagging behind, making diplomacy and collaboration important and choices more difficult as more factions can pounce on your earlier in the game.

This also makes certain early bonuses more important in certain settings.  Such as early attack/defense bonus in a slow warfare technology game, or an early production/research bonus in a slow colonization technology game.