I fail to see how the defib is unbalanced as it already has the major downside of revealing that you're a T on the scoreboard and in addition to that you loose your T shop credits and your weapons as well.
I don't think that this would balance the defib and would rather nerf it to a point where people won't use it anymore.
I think its fine how it is.

The downside of it revealing you as a traitor is completely irrelevent as long as the person using the defib is not a total idiot and has the patience to wait. If used early into a round then yes it sucks because everyone is hunting you and there are a lot of innocents, but if used late into the round having traitors be defibed at 100hp can almost always secure a traitor win. Even if you know exactly who the traitors that got rezed are good luck fighting multiple multiple rezes traitors at full health while you most likely are weak because its late into the round and there are few remaining innocents.
As for credits and weapons they are everywhere and not hard to come by, with how many traitors and detectives there are on a server with 47 people there are always credits to be found or gifted to the rezed traitor. As an innocent playing a round against like 7 traitors and then seeing 2/3 of them being rezed towards the end of the round is just annoying because even knowing they are traitors you still cant fight them. If you die as a traitor you should be punished, getting rezed at full hp is too forgiving.