What would really be interesting is that each race has it's own tech tree full of different techs that are unique to that race. Different weapon systems and damages different sizes for modules. With just the one tech tree for all the races you already know what is coming but if each race had differnet stuff and once the AI gets better at creating new ship designs then we're talking coolness...

Some items that come to mind are Boarding parties to steal ships, Lasers that penatrate armor, Working with Shield Harmonics, Robotic Ships, Stardocks that can repair a ship but have no defense ability. Damaged ships from battle that need to be tugged back etc. Planet launched missles, Starbases that can attack a planets defenses ( great if your planet is successfully invaded). Sector Minefields just some ideas