I am of the philosophy that a better line will help the receivers we do have get open.
I will not debate you about the quality of the WR; it is not as good as it could be -- and teams know it because they bracket or straight-up double-cover Diggs on most plays.
IMHO, if we can man block on the OL, then the RBs and/or TEs will draw man coverage by LBs or find openings in the zone coverage if teams insist on doubling on Diggs. Moreover, the opposing defences will then need to respect the run, which will help our lesser receivers find soft spots in zone coverage.
Just my preference. Most fans are not as line-oriented as I am.