Kadri is a lost cause, and I am sure Washington is fed up with Wilson by now too... But at least he won a Cup for them first.
Leafs need to take out guys like Simmonds and add grit guys who can do other things. That way you have a reason to put Simmonds out there for more than 8 minutes a game. Tampa is not putting out physical guys just so they can hit. That is why they dumped Erne, Callaghan, etc. in the first place. They want them to score, or at least prevent the other team from scoring while their scorers rest. If Simmonds can't do any of that, and really he could not, then why should he play more?
And you don't even need to pay a lot for those guys. They are out there, and many of them are not overly expensive either. We've got Mikheyev, Semyonov, Brooks, Anderson, Simmonds, and Spezza for our 4th line. I think we are fine in that area. Mikheyev or Anderson may even play 3rd line.
So you need a couple of guys, and there are some solid options. Foligno, local guys like McGinn and Goodrow, guys like Armia, etc. None of them are earth shattering, but they should give an honest and consistent effort in a bottom 6, and then you just look for some guys who can outperform expectations a little bit.