one further argument against the prisoner...

once you have him in this state of the game, you will put him into your defense, no matter what. He is a must have atm if you want to have a great defense.
Yeah there are more great defenses without him, but he is the most powerfull character in PVP atm.
So if nothing changes in a few months 90% of all defenses will have a prisoner in it, because there is no way around. That's the best proof how imbalanced the situation is atm. Once you got him he is part of your team. We need at least one or two more characters with the same passive and things would be better i think. Or if the passive removes also the own passives things would also be better IMO.

Nicko mentioned several times, that prisoners are popping up like mad in PVP. IMO that's a big bias. They are not popping up like mad, it's simply
that the guys who have him, will be at the top of the PVP leaderbord most likely. So most you see is prisoners out there in the top 25.

Do you really want to play against same defenses again and again? This is really hurting the game dynamics.