FHQ is OP or UP depending on the map. Ettlebruck for example. Get the central building and its basically GG.
Precisely why the Soviet FHQ should be repairable but just be a separate building that's created by your units (and then probably require heavy rebalancing, of course).
I just can't see how the gimmick can be healthy and stable gameplay without causing the FHQ to be entirely the same no matter what garrisoned building it's built out of, negating the entire point of the gimmick anyway. It should just go.