Looking at the tech trees (specifically just the population increase techs) wouldn't it make more sense for the Vasari's starting home planet to be a volcanic one? And the Advent's a desert planet? TEC get the biggest upgrade out of terran planets, no brainer. Vasari get the biggest population upgrade to volcanic and the Advent get desert. Now obviously the Vasari got the short stick by quite a bit.

Wouldn't it make more sense for the Vasari to have their max population on volcanic planets match the 280 base that TEC receive on their biggest planet upgrade? Likewise for the Advent. I understand that essentially it means the Vasari would succumb to not having crystal in the very beginning. This would indeed cause a huge problem. In an extreme case the costs of units, structures, and upgrades (early ones) could be reworked to only include metal for them, obviously a larger sum of metal than what is needed now to compensate for the crystal they don't need then.

Planet stats would change depending on which race you're playing as. TEC get terran (+30%), desert (+15%), and ice (+15%). Advent get desert (+30%) and terran (+15%). Vasari get volcanic (+30%), terran (+15%), and ice (+15%). So simply give Vasari's the 280 base on volcanic and the Advent a 280 base on desert.

So say we change the planets to something along these lines (TEC stays the same)
Advent: Desert 280 base, ice 190 base (change the terran tech to ice), terran 160 base, volcanic 70 base
Vasari: Volcanic 280 base, terran 190 base, desert 160 base, ice 70 base

Not that any of the effects matter too much but as it is now, TEC forces get the biggest bang for their population cap increase techs (cost wise and population) than the Vasari (T4/5 for the minimal credit boost upgrading volcanic), the Advent not as much since their population upgrades are cheap too but still receive less population to a lesser extent. Reworking their starting costs and planet would do a couple of things. First, each race is looking out to gain different types of planets and second, each race starts with a different priority of how they want to go about doing things. It'd be a nice change of pace and add in some more gameplay differences between them. And other than the reworking of the initial starting techs (T1, maybe T2-T3) it'd basically just be switching around planet stats per race, minus the TEC since theirs already makes sense.

The game does a really good job of mixing up the planet types to get an even balance between all of them (minus some premades) so that shouldn't be too much of a problem. Can't think of anything else that would cause problems using a setup like this.

Understandly it'd be a lot of balancing issues and it's probably not going to happen. I just thought I'd throw something out there that's I've been thinking about    It's late also, I tried giving details and even replayed a game to grab some numbers so, sorry if I missed something.