The only limitation is number of declared wardecs based on Omega count of that Corp.
This can be sidestepped by creating sub-Corps with their own wardec cap.
The isk cost of wardec in my proposal is inversly scalar, and fair to both larger and smaller Corps, in proportion. Larger Corps also get a cheap rate vs even larger Corps.
How you finance that war, is up to players.
A big Corp wont pay more/less than a smaller Corp, in proportion to their target. Such that a 1000 Omega Corp wardeccing a 1100 Omega Corp pays the same as a 1 Omega Corp wardeccing a 100 Omega Corp.