It seems like every team in the NFL would like to upgrade their offensive line. And the problem of depth is universal.
Having said that, I agree with the premise of this thread: this is a solid line and considering all the needs this team has, investing in the o-line should not be a high priority. Yes, if you can get an affordable stud FA or find a gem int he draft to improve along that line, do it. But big spending or high draft choices should not be an off-season priority, The people we have are solid, they need to stay healthy and a better scheme (coaching) that fits them--like in the two years previous to this season.