It is also what i think, but two new demigods seems like a wiser idea if the decs don't want to see endless whinning about the fact that one side has 5 demigods and the other 4.
Well what they could do is nerf the damage and health of all of demigods on the side with five by 20% to counterbalance the disproportion.
Really though it's a good question, and one I think Frogboy asked directly - would players be more upset about waiting longer to get any new DGs at all or would they get more agitated by having a disproportionate amount of DGs? Personally I'd rather just get one as soon as it's ready, I'd gladly deal with disproportionate sides (in quantity, not fairness/power/balance) while waiting on the second.