When we last played the Pats, Gronkowski mentioned that he aspired to be the complete TE that Witten is. Catching TDs is great but what he does he does better than any player at his position in league history. He does it all. He doesn't do any one piece of it the best but the combination makes him the best ever.
He's too slow yet he gets open, he doesn't break tackles but he doesn't fumble or run his routes short, he's not really big for a TE but none have mastered better using his body as a shield to give his QB a safe target, his awareness of what is going on in the game and situational football is on a coach's level and few TE's have ever been the leader he has been to his teammates.
Two events will always stick in my mind about Witten. In 2014, the RB was coming around the left side and Witten pointed for him to go around his backside and then delivered the block and I'd never seen such awareness and calm in a player like that and the other was when Dez was blowing up in the locker room at some local media and Witten halted his interview and just walked over by Dez and stood there and silently diffused the situation. That spoke volumes to me about his leadership role on the team. Irvin was a demonstrative and vocal leader but Witten is just as effective, just demonstrates his leadership in a more low key manner.
If anyone were to ask me to show them a football player, Jason Witten would be the first I would pick to show them what makes a football player.