I think part of the concern with DB's is that WR and TE seem to be getting bigger and harder to defend on height and harder to tackle on weight.
And more teams are going to 3 or 4 WR plus 1 or 2 TE sets all the time, so you have to keep 5 DB types on the field a lot to cover these guys, limiting the number of LB's who can stay on the field. So defenses stuck in some type of nickel quite a bit.
If you could find a LB who could stop the run , and blitz, their main jobs I think, but also cover atleast a big TE closely that would be a bonus.
Interesting Bleacher report ranked top 100 CB
http://bleacherreport.com/articles/1...00-cornerbacks
and they have three Texans CB's on our roster in top 50, which is pretty good.
Karrem Jackson at 48 ( this is ahead of some big names like Patrick Paterson)
Brice McCain at 22 ( very high at the slot CB)
Jonathan Joseph at 5 (obviiously top tier)
I guess bigger DB's to help defend bigger receivers will likely become a trend of sorts, but speed needs to be there and tackling ability.