It really isn't. We've got 5 TEs on the roster. With the exception of Hanna, who's been on the roster since 2012, none of them are speed TEs. In fact, they're all slower than Witten was coming out (4.55 in the 40) by a fair margin.
You have to stop and think about what they're trying to do on offense when they put the team together. They want guys who can block inline, in space, and who can catch outlet passes in the passing game. They aren't a team that tries to stretch the coverage with a speed mismatch from the TE. We're a run first team that uses the big guys to block.
That's not going to change just because you guys want it to change. If we're going to add speed, though, it'll come from a replacement for Butler at WR or through the addition of a 3rd down back who's a coverage mismatch like we had in Dunbar and were reportedly looking for in Pumphrey last season.
Hanna - Combine
40 Yrd Dash: 4.49
20 Yrd Dash: 2.67
10 Yrd Dash: 1.57
Swaim - pro day
40 Yrd Dash: 4.71
20 Yrd Dash: 2.73
10 Yrd Dash: 1.66
Jarwin - pro day
40 Yrd Dash: 4.73
20 Yrd Dash: 2.76
10 Yrd Dash: 1.58
Gathers - pro day
40 Yrd Dash: 4.79
20 Yrd Dash: 2.79
10 Yrd Dash: 1.71