I'm also on the "interior line early" bandwagon. My ideal handling of the OL this offseason would be to cut Connolly (save $3M), sign Svitek to another 1-year swing backup deal, get the best center in the draft, and either re-sign Wendell to a backup (~$2M average per year) deal or grab a swing backup in free agency or in the middle of the draft. I think our main difference is that you'd take a top rookie RG, where I think Cannon deserves a chance to take that spot.
Then my ideal starting OL is Solder, Mankins, a rookie, Cannon, and Vollmer, with Svitek as the starting tackle and some combination of Wendell (probably unlikely), a reasonably cheap free-agent, or a mid-round rookie as the primary interior backup. The tackles have both been phenomenal this season and are under contract for a few more seasons, but that doesn't do much good if opposing defenses can get interior pressure semi-regularly. I can't justify to myself the idea of both paying Wendell starting center money and Connolly $3M salary next season just to have them waste the great pass blocking by the tackles.