The problem right now is how to challenge a survivor with CBMs or mutations.
Game balance wise a vanilla fully survivor equipped character with decent skills (6+), can mostly deal with any threat pretty easily save for a hulk, and even that isn’t too bad if you have a good weapon/martial style - there are of course chicken walkers, but their weapons are so powerful that it doesn’t really matter too much what your build is in most cases, you simply don’t want to trade fire with them.
Game kinda needs some late game threats that bridge the gulf between Hulk/Shocker Brute, and the insta-gib capable Chicken Walkers. The new rifle armed security bots are a nice addition in that category. There are some semi-threats like the flaming eyes and I guess the Shoggoth? But you almost never encounter those so… Not quite sure where the Jabberwock actually sits in the overall threat range. Most of these just never show up though, and even finding an environment where they might show up is difficult, and generally offer no story or reward draws to encourage you to go to them.
Like, sure, you CAN go wading into a triffid forest, but I’m still unclear on why you’d ever bother other than just to test how strong you are against some of the bigger ones.
The sub-hulk range has filled out a lot lately with the shadows, juggernaughts, and some upgraded versions of the low level zombies, but post-hulk is still slim pickings - and that’s where any CBM/Mutate character is looking for challenges. Until that end of the rogue’s gallery starts to fill out some more, I’m not sure it matters how the CBMs and mutations are balanced?