Basically the definition of "guy". Pretty tough to have a strong opinion on this one.
Probably the best thing about him is that he's still only 23, already has 192 NHL games under his belt, and has scored 60 points in those games. If he can play 10 minutes a night, not cost us any goals, and then chip in with some points, I don't know what more you can ask of the guy at league minimum.
I'll agree somewhat that he's just "Guy" but he had an 18 goal, 35 point pace season at 21 with Florida (11G, 11A, 22P in 55GP) so clearly there's some ability to be tapped into there.
And additionally, if the Leafs are going to improve their defence, and by all indications it really sounds like they want to, potentially going for the big fish in Pietrangelo, they'll need more "Guy"s and Malgin can be a pretty good one of them at a great cost.
Leafs can always send to the minors and it doesn't hurt the Leafs cap. There is an opportunity for Malgin to get bigger minutes. Kapanen and likely Johnsson have/will be gone from last seasons wingers.