Mathis is the only guy that I would say should be a definite upgrade over what we had last year. We haven't really had a strong pass rusher since Randy Gregory, and boy have we needed it.
The rest of the guys on DL haven't exactly shined to date, but they're mostly young, and it's a little hard to get a feel for their potential considering that we're probably going to be using more 4-man fronts this year. Similar story for the LBs, partly for the same reason.
Kicker and punter almost HAVE to be upgrades - it would be hard to find guys who are even worse.
RBs I don't think will be much better in talent, but will hopefully be much better in coaching.
Same story for WRs. On paper, Frost has done a good job of recruiting them, but getting them to actually stick around and contribute to their full potential has been abysmal. Hopefully Joseph can change that.
QB I think will be a side-grade overall, but could look a lot better with better guys around him. Which mostly depends on...
The OL is still the scariest group on the team. I don't know if Raiola is a better coach or not, but even if he is, it'll probably take a while for him to get things turned around. Mostly it's gonna come down to whether guys can stay healthy, and if guys coming back from injury are able to play at their previous level.
Long story short, this team will be exactly as good as its lines allow it to be.