I'm fine with if Kakko becomes a defensive power forward, but my biggest issue with his play is he's not mean enough to create space. Jagr is widely considered the blueprint as far as a puck control in the corners, clean player, yet even he would throw an elbow in the corner, or throw you off him if you tried to hook or hold him. Some of that was how he got the space to score all the points he did. Not only would he physically dominate you and wear you out, but you were going to come away with a few bumps and bruises, and if you retaliated, you were either going to end up shorthanded, or Jagr would just laugh it off and keep outworking you along the wall.
While he got to 40 points last year, I'd hardly say he's a lock for it in a given season. The game is only getting faster. He can't be slow and try to play a big man's game but be afraid to be mean every once in a while. He's strong on the puck, but he's not strong enough on the puck, and he doesn't seem to have the sheer willpower to get off the wall under an average defenseman's pressure.
I really think he needs to cut the happy go lucky crap, nice guy, Lady Byng contender...and go Dark Kakko when he comes back.