They have a better pass receiving TE than Witten, he actually breaks tackles.
Witten's greatest attribute was the same as Emmitt's and it is vastly underrated, durability. They were like blocks of granite. I think as players Gronkowski and Olson are both better TE's but neither could come close to that durability part of it. You always knew he'd be there and you'd get his best every time he was there.
I don't know how he fits McC's offense or what the other options might be. Do they think Jarwin and Schultz can be the 1-2?