Yeah, maybe they don't come in and win jobs.  But competition breeds improvement and the current guys on campus will realize early on that these 7 lineman coming in, aren't coming in to sit and watch.  The defensive line I expect to see Rocker using 6-8 in rotation instead of his 3-5 from last year.  So I think everyone in that group will be competing for more snaps all year.
On the offensive line Wright is coming in to be a starting tackle, and unless he comes in grossly out of shape I expect him, Morris, Jahmir, and Tatum will be in a battle from the beginning.  Guard depth will allow the staff to find their best 3 for that interior, since it seems Carvin could be a potential center instead of a guard.