re: Which sophomore do you think makes the biggest impact this season?

It's becoming apparent to me that the 2015 recruiting class might be the best in LSU history, even though it was only ranked sixth (I think).

Arden Key is definitely the best of the bunch so far. In fact, he's the only guy I would say projects in the top half of the first round, whereas 2014 has three in Fournette, Adams, and Malachi.

But just look at the top seven guys in that class. There's not a miss among them.
Toliver, Tyron Johnson, Maea, Guice, Donte, Key,and Weathersby.
All of these guys have All-SEC potential right now. And if you peruse the rest of that class you notice very few busts, several lower ranked players who contributed as freshmen, and lot's of potentials who are at positions that need time to develop.
2015 Class