The Titans roster seems pretty bad to be honest. I'm not expecting Washington's OL play to be bad this year with Trent Williams and Scherff bookending (NFL half slide protections work similar to coverages in a way, so the ability to leave Williams on an island should help Scherff) but their defense isn't very good and obviously the biggest question is at QB. I wouldn't call the Pats' roster great currently. In Wilfork and Revis they lost probably their 2nd and 4th best players, and their 1st and 2nd best defenders. Brown doesn't replace Wilfork, and rather than replacing Revis they also lost Browner. Saying CB is "a bit of a question" in New England is like saying the Iraq-Syria situation is "a bit of fisticuffs." Any other team with that CB situation would be up **** creek, but NE are the ultimate benefit of the doubt team because of Brady, BB and their offense.
I'm not remotely convinced about the Raiders either. The thing with Derek Carr is that he's a very conservative decision maker and I'm not sure he improves as fast as people think he will. Teams seem to find it easier to take a naturally over-aggressive QB (P Manning, Luck, Tannehill, Big Ben) and rein him in a bit than they do to get someone like Carr to cut loose and make the throws he will eventually need to to win NFL games.
People are extremely low on the Bears this year but I think that might be partly because of an overreaction to how disappointing they were compared to last season's expectations. Also the 49ers now have a pretty weak roster especially if you don't consider their QB to be very good, and that guy will be getting a new coach this year.
Also Buffalo have a pretty good roster all around, but so did the 2012 Chiefs and Matt Cassel still lead them to a #1 overall pick, so that's worth thinking about.