
Once built, this building would allow upgrading units/defence structures/whatnot.
For example, there's an endless debate whether MiG's should have AA or not. What if it was an upgrade that you could purchase?
Tanks don't have enough armour? Well, you could purchase an armour upgrade!
Fake structures don't provide build radius? Buy an upgrade!
SAM sites have poor radius? Upgrade!
This way each faction can be even more unique, with their own upgrades.
Anything you wish can be implemented. Please don't focus on my examples because they're only examples. I want to discuss this feature as a RA game mechanic and how it could potentially improve the gameplay.
P.S. I think it should be possible to implement it as a modded map because d2k already has upgrades, so the engine supports this kind of mechanic.