All of that simply to say that I do not see how the Lions cannot take a franchise LT with their first pick.
If there is a franchise LT in this draft I don't think he would be available at pick #13. That said, they do realize that improving the O-line is an off-season priority, even though only 5 teams allowed fewer sacks last season. The only 1 of this group not returning is RT Cherilus due to injury, and Hilliard played very well (better than Cherilus, IMO) in his place after he went down. Fox is a LT they took in the 4th round last year to develop, and showed some promise as a rookie last season. The only reason he slipped to the 4th round last year was due to injury concerns, and he stayed healthy throughout last season.
The back 7 is the area that needs the most improvement. Levy is the only NFL quality starter of the LB core, Carpenter and Palmer are decent back-ups that will be thrust into starting roles if the status quo remains. Houston (a UFA right now) is their #1 CB that must be re-signed. He would be a #2 CB on most teams. Delmas is a good Safety, but they have had crap lining up along side him.
Detroit has done a very good job recently of picking up quality players during FA, and trades involving late round picks, for talented players that did not fit other teams schemes (Houston, Rob Sims, Alphonso Smith, Scheffler, Burleson). This is why this off-season has been very frustrating. Had Free Agency started already, I'm sure that some of these back 7 positions of need would have already been addressed. Would love a signing of LB's Tulloch or Lawson, a Center to replace Raiola, and a Safety to play along side Delmas.
All this being said, I think Detroit would be best served by taking the BPA at #13 of the following:
1. Tyron Smith (would start immediately at RT and hopefully take over for Backus in 2012)
2. Prince Amukamara (#1 CB they desperately need)
3. Anthony Castonzo (see Smith above)
I would love the idea of trading down down and getting Castonzo or Carimi later in the 1st while getting an extra pick, but if Smith or Amukamara are there for the taking at #13 I will be thrilled with either.