Yeah, he's gotten quite a bit better as he's eased into Opeth. Even comparing the Albert Hall performance to Roundhouse Tapes, he sounds much more sure of himself and comfortable, and seems to have gotten a better feel for the music. Comparing the two different live versions of Bleak is a great example...he absolutely BUTCHERED the intro groove on roundhouses, but actually pulled it off fairly well at Albert Hall. I saw them shortly after Axe officially replaced Lopez and found myself cringing at parts (Windowpane, especially), but it does seem like he's improved. Should be interesting to hear him again on the new tour.
I wasn't a huge fan of his playing on Watershed, TBH. It wasn't bad, and he's got chops, but his playing "felt" like a typical metal drummer, and his repetitive fills got a little monotonous (e.g.: burden).