I know people have asked for "New Units" to be put in the game before, things like super heavy tanks or battle cruisers and thinks like that.   However would an "Upgrade List" for the units we currently have not be just as good, or at least different.

No need to go over board with upgrades but have maybe 5 of them in total.

For example you can buy a defense station.

So why not have a list of 5 unit upgrades that are a 1 off payment.

- Fit Advanced Shielding
- Increase Weapon Systems
- Train Combat Medics
- Increase Droid Armour
- Fit Warp Engines
- Weponise Transports
- Life Form Scanners on E-Ships
- Train Home Reserve Army

Each 1 upgrade would either be expensive, or each player could be capped on the number (2 only) for example so each empire can advance their troops in their own way. 

I guess overall "upgrades" as it were give a player more to fight for, more to work towards, and this would be a simple way of changing the units without adding new ones.

Just a thought