1. It's a myth Tauscher spurred Packers' offensive turnaround
2. Should be able to replace performance level
3. The big one: It's past time to move on
Those are all good points.
I don't know if it's a full-fledged myth that he spurred their offensive turnaround, but I agree that he didn't turn them into a great offense all by himself. The second point is his best point: RT Allen Barbre was so bad that anyone would have been a major improvement.
His third point is the trouble. While OL T.J. Lang is good enough to start, there is no one behind him. See Greg's depth chart here. I want LG Daryn Colledge gone, so OL Jason Spitz moves into the starting left guard spot. Then if Lang starts, it leaves three guys (Barbre, RT Breno Giacomini, C Evan Dietrich-Smith) who should be battling for their roster spot lives. They could draft someone, but draft choices don't always work out, and they certainly know what they're getting with Tauscher. Lang should be the top backup, and he's certain to get some playing time based on all the injuries they played through last season.
NFL Mock Draft point: While most mock drafts have the Packers selecting an offensive lineman at No. 23 overall, signing Tauscher has to eliminate that thinking. Any lineman drafted would start the season no better than 7th on the depth chart, and he shouldn't be needed in 2011 either because LT Chad Clifton and Tauscher just signed for multiple years. Drafting an offensive lineman high also seems misguided when the top remaining priority should be finding a pass rusher to replace LB Aaron Kampman and to complement LB Clay Matthews. LB Brad Jones is a good pass rusher, but he's not someone who would ever demand a double team.