hes stiff and slow. thats his limitation. hes not very athletic..more of a 2 down player
He plays faster than he times, and he's timed in the 4.6 range. He doesn't have great top end speed, but he's very athletic for his size (don't know where you're getting that he's not athletic), and he's agile for the position, as well.
Really, He didn't look stiff, slow, and without athletic ability when I witnessed him chasing RB's down from behind, beating McFadden to the edge and stuffing him, coming off the edge to get the sack, or when I watched him blitz up the gut and nail the QB. You don't make the All-SEC team at LB, and make as many tackles as he has if you can't hang.
One of the things I've noticed that tells me he could be very effective in NE's system is his understanding of coverages. He also gets good depth and has good range in zone. Also, he has good sideline-to-sideline ability, takes good angles, rarely bites, and he's a strong open field tackler.
Keep in mind Goff's playing in the SEC against top level speed, then take the fallowing into consideration:
"LB Jonathan Goff has been one of the SEC's most consistent linebackers for the last two years. A two-time team captain, Goff finished this season as the league's third leading tackler with a career-high 113 stops. He also posted at least 12 total tackles in each of his last three games, and had 10 tackles or more in five of his final six performances.
"Considered for the Nagurski and Bednarik awards, Goff started 40 consecutive games at middle linebacker for the Commodores."
http://www.nfldraftscout.com/ratings/profile.php?pyid=17529
Career stats: 47 games, 307 total tackles (third among all active SEC players), 15.5 tackles for loss, 6.5 sacks, 14 PD's, and 3 INT's.
He's got a strong muscular build, but he's also got a pretty big frame, and still has room to grow. Overall, I like his leadership ability, intellect, understanding of coverages, tackling ability, and size. I'd take him in the second round in a heart beat.