They've only had 1 SB appearance in the past 5 seasons anyway. The defense is being retooled and that was arguably a bigger reason for the dynasty than the offense. Once that core group of guys started aging, they morphed into a fantasy monster that just won divisions. They drafted some nice young defensive players last year that will develop alongside the haul they bring in this year. They also drafted a young man last year by the name of Brandon Tate who was a teammate of, and more highly regarded than, Hakeem Nicks at UNC before suffering a season-ending injury in college that rendered him useless last season. If he returns healthy this year he could open some eyes alongside Moss and Edelman until WW gets back into game shape, so I'm not overly concerned that the offense will suddenly fall off the face of the planet when Moss leaves.
As for the Moss/Welker discussion.. I think Moss's stats are far more reliant upon Welker being there than vice versa. Thinking back, when has Randy ever been dominant without a "1A" type receiver present? If anything, next year's Randy Moss fantasy draft stock should slide into the 2nd tier of WR's if Welker's not 100% to start week 1. Edelman proved he can fill in admirably, but he simply won't draw the attention that Welker normally does. Not initially anyway.