I remember the reason why Boss Wolf was nerfed so badly because people complained pairing him and Guin would make them impossible to defeat.
I may be biased since I got Boss Wolf and have been leveling him up, but I believe such an issue is not legitimate for the following reasons:
1/ Both Guin and Boss Wolf is meant for the tank position, which means if you got both of them you gotta choose either of them for the tank position. Of course they both can flank but that would make them lose 60-70% of their usefulness. I think any experienced players know this.
2/ If Boss Wolf hadn’t been nerfed but possessed his original stats, that of course would make him way stronger, but still he wouldn’t be invincible but probably at the same level as current Guin, which is so popular among top players. Well, people would have had one more choice for the tank position, which I guess is a positive thing.
3/ When you fight Guin tank or the OP Boss Wolf that could have been, you gotta stack purple (or yellow) and you always aim to kill her (him) before they go off. Based on my experience, you only got 20-30% chance to win after Guin goes off. By then whichever hero put behind her wouldn’t matter much (you know what I mean). And let’s say once Guin or the could-have-been OP Boss Wolf is killed, would you prefer to have Zel, GM, Magni, Lianna on the flanks or a Boss Wolf / Guin?
I think the devs (with all due respect) decided to nerf Boss Wolf too quickly (I know there is a thread for this issue). Due to the formation of your defense team, there can only be one tank, and thus you can’t squeeze 2 perceived OP heroes that possess great tank materials into one defense team and expect them to be both OP.
So devs, please take this into consideration for future hero creations.