"90% wooded with moderate to steep grades" sounds like my property, and my uses are very similar as well. Since you did not mention mowing (I don't use mine for mowing), then the general consensus that the subcompacts are better "lawnmowers" is not a factor.
I started out with a subcompact (JD2210) similar to the BX, meaning lower ground clearance (~ 7") and smaller diameter tires. It was a good machine, but not great for working in the woods, with significantly limited access to some areas. I sold the 2210 and bought a compact (B7500), which was a costly change, a lot more expensive than buying the bigger machine in the first place.
The CK20 has bigger tires which will improve traction. My only concern is how much the backhoe subframe reduces the ground clearance at all times, even with the BH removed. My B7500 3 point backhoe (4672A) can be completely removed when necessary. Having said that, the 4672A is hard to install/remove, not very rigid, and digs no deeper than the BX.
Regarding gear vs. hydro, I love my HST, and would never go back to gear. Just my two cents...