Though I do agree that the TE is the only position that might have been downgraded, don't be surprised if that question was asked to McDaniel or any of the Offense coaching, they might tell you they actually upgraded.
McDaniel wanted to get better blocking from that TE position over better receiving skills, so this to him might be better then last year.
If you look at the Miami Offense, and all the receiving weapons they have at WR and RB, expecting much from the TE position receiving wise might not have been as vital, as making sure when needed they can block, with the added receptions here and there.
Don't get me wrong, I'm sure if McDaniel was able to get a complete TE that can do both equally well, he would jump on it, but for now it's blocking he needs most from the TE position to succeed, and maybe make Miami Super.
For now, Higgins seems to look more and more like a very intriguing project for the Dolphins coaches to create their version of the all purpose starting TE eventually.