i was thinking of something like that, maybe summons cost gems to maintain, and will either
A
wly drain your lab supply
B
rain commanders held supply if no lab is present or
C
wly decay/lose health overtime
this would be a realatively small amount (a percentage of summon cost perhaps) and although would trouble small amounts of summons would easily start to cripple players with large amounts of said creatures unless they clam in which case they will have a big advantage wether this rule exists or not (and clamming hopefully will be harder in dom3)