I think next off-season we will know more. In my mind in addition to his new contract the Haula situation also impacts him.
1) If Haula is not resigned due to costing too much / injuries / whatever the 3C spot opens. For that Canes have couple of options: Necas, Wallmark and UFA as 2/3C. I personally don't think Necas is yet ready for the center responsibilities and Borg won't commit the big pucks that good UFA centermen command. Therefore in this scenario I believe Wallmark will be the stopgap for Necas/Suzuki etc.
2) if Borg can negotiate 2-3 year deal with reasonable cap for Haula the situation is completely different. Wallmark could become tradebait/expansion draft fodder as with a new extension he could become overpriced luxury as 4C.
I've been impressed by him as he is more than adequate 3C and can even fill in for too 6. Ideal middle sixer, I view him in the same mould and Dzingel, 3rd liner who can fill in in a pinch. He's also versatile guy who can play both special team.
He should be the 3C but with Aho, Haula/Necas, Staal he's currently blocked. I even believe he should have switched positions with Staal already. I also believe Staal should be the 3C next season meaning Canes are lacking 2C. Unfortunately Wally wouldn't be an option for this spot.
He's too good for 4C but not good enough for 2C. If he has cheap contract, he can continue being great insurance policy as 4C. However, with Svech/Dougie extensions coming guys like Luostarinen, Bishop or even Martinook should be used in this role.