I don't think there is any question a fair amount of this is honorary for his career, but I don't think he would be voted in if people thought he wasn't still a pretty good player.
I think what Cowboy fans have to realize is the offense is shifting, and while a younger talent at TE would be helpful, Witten still has a place, though in a lesser role than in the past. A better passing game between the QB and WRs would mitigate the need for a younger, elite TE, just as a younger, elite TE would mitigate the need for upgrades in other areas. No team has it all.