Skating isn't great, he's not the biggest.. and he's really the 3rd wheel on that line even if somehow he has more points than them.
There's definable qualities of his linemates.. Smith's high end IQ, his anticipation, playmaking, and hands with a proficient ability to steal pucks make him the architect of most of what happens when the 3 are on the ice.
Leonard is a bulldog, he's the guy digging the pucks out, going to the net, being physical, but he has a fair amount of skill as well, a heavy shot, good hands, and a playmaking game.
Perreault isn't doing the grunt work that Leonard is doing.. he isn't the architect of the whole thing like Smith. He's got good talent and he's able to play off of those guys and keep things moving, and there's definitely a career in that.. but he's got more to overcome and he's a complement rather than the driver.
That's why I said above it's strange how much of an aberration his point totals are where he's clearly the least effective player on the line but has the most points of the 3.