My concern over Kapanen is that his speed was almost utterly wasted on the 4th line. Yes, he has shown that he can win a footrace to reach the puck just before it goes into the corner in the offensive zone. But his size made it difficult for him to cut to the net with the puck. Worse, he was easily moved off the puck when the D arrived 2 strides later. Kap's ability to get off a shot on net while heading into the corner in the offensive zone all alone was quite limited.
Instead, what we saw time and again in the playoffs was Kap streaking into the offensive zone in an impressive foot race, reaching the puck a stride ahead and having to hold up while the rest of his line caught up. The advantage was lost and essentially, nothing really came of it. The opportunity for a quality scoring chance was gone. I recall only one quality shot at the net that Kapanen managed on his own while winning such a footrace. There would have been more, but Martin and Boyle were too slow.
Poor juices to come off such an appetizing steak, time and again.
Sure, we can bicker about the usefulness of at least having the puck in the offensive zone for a time. But the consistent results of these races to the puck shows that Kapanen is miscast. 95% of the time, there is a temporary puck retrieval without a scoring chance arising from it. Babs can do better.
Had Kap been on a line with Nylander, Marner, or perhaps even Brown, Matthews or Kadri, there would have been another line mate who was fast enough to reach the offensive zone in time ahead of the pack to receive a pass from Kap in the offensive zone to yield a quality scoring chance.
So while I was impressed with Kapanen's speed, it was almost entirely wasted on the 4th line. This guy needs to be playing with at least one other fast-skating Leaf on his line or his greatest strength is wasted. After Kap's speed is wasted, his shot isn't enough to make up for his reduced size and difficulty in winning puck battles.
In short, I am in favour of Kapenen on the top 9. But as a 4th liner? I'm not convinced he's all that useful a skater for the Leafs. He's too small and he tends to lose puck battles.
But put him up with Hyman and Matthews - he might be productive as hell.