[Corinthian]

Because they were pointless as commanders and using them requires massing them. So having 10 of them would just clutter up the screen for you if they were commanders.

As for the Zmeys, yea iv'e always considered them very powerful. Even back when they costed 35f. But an easy counter should be Shishis as I dont think it got any magic attacks to pierce mistform. I might be wrong about the fire being non-magical and if I am you have to put a Fire ring on them though.