I honestly don't think it's a good a matchup against DK. Shine is nice if you get up close, but that won't be happening a whole lot against a good DK. Also, if shine is blocked he can OOS Punch or UpB SA to beat out any attacks after. Or you can roll away which doesn't give Wolf many followups options other than Fsmash or Blaster.
Wolf Fsmash can be punished easily with DK's range. Blaster isn't too bad of a projectile for him to deal with. You can't tilt cancel it but it's slow, which is both good and bad. It's good because it stays out a while and makes it tougher for DK's big frame to spot/airdodge through, but being slower means he can maneuver around it decently with a jump.
Other than that DK outranges and pretty much outprioritizes Wolf on just about everything, air and ground. Wolf can't KO DK reliably until 150%+, and that's if he saves his Dsmash and Fair for kill moves. Whereas DK can get reliable % kills in the 80-90%s, even earlier if he gets Wolf off the edge at lower %.