[Ming]

KO,

I have not tested this, but it seems to me that by the time Ophanim is available, Merkavah is not far behind and it is very tempting to wait and get Chayot rather than spending the gems on just Ophanim unless Ashdod is in the mids of a life and death struggle and cannot wait.

Chayots are awesome, but they are not unique and so other nations can get it through wish. So it should not be too unbalancing.