I'm kind of growing tired of systems that have a multitude of sentient races living within one biosphere; from an evolutionary standpoint, is it possible to have intelligent goblins, farrow, pigmen, gatormen, elves (of various sub species), trolls, and humans living or having come into existance all at once? Likewise, I'm bored with the games where you have different races from different planets, but said races can only use equipment from their race... because, you know, never in the history of reality or cinema has one group of people proliferated or utilized another culture's technology.
So I would like to see a couple different games based off of this idea.
1. A game where there is one race, all on the same planet. You can have vehicles or devices specific to one's army, but you can also use devices from another's. Think of it like this: if you were playing as the US, you'd be the only ones able to use the stealth bomber... but if you were allied, you all could use the F22... but if you were of an enemy force, you could use allied land vehicles because capturing or repairing those are more feasible and realistic. You can then make rules for different factions, but they all can use the same set of cards or models.
2. A game where there are different alien races from different planets, each with their own tech tree, but have it set up so that you can use echnology from races that are similar to yours... the further away from you they are, the less likely you can use it. There would have to be a spectrum, like a color wheel. Those aliens immediately connected to your left and right can share freely; two places out there would be a penalty, the further away, the harsher the penalty. Those directly across from you are complete opposites, and you are unable to use or even comprehend their devices.