Wallace has always been a deep threat, body-catcher with questionable hands. Nothing has changed.
- Wallace needs a QB who can hit him deep in stride. Roesthlisberger could do that. Tannehill can not.
- Wallace needs an offense that utilizes his strengths, and works around his weaknesses. Steelers were able to do that. Sherman & Miami have not.
Put it this way: For several years, Mike Wallace performed as the top deep threat WR in the NFL. On the other hand, Tannehill has never shown deep ball accuracy. So if the Tannehill-Wallace deep ball isn't clicking, it's far more likely that it's because of Tannehill or Sherman.
If you've watched Mike Wallace over the last few years, you'll know that nothing about him has changed (except who is throwing him the ball). He has not come to Miami, and turned into a different player. He runs, catches, and plays the exact same way that he always has. If you thought throwing $60 million at him would turn him into Megatron, you're going to be disappointed.
Ultimately, Mike Wallace might not be a good fit with Tannehill (inaccurate deep ball), or a west coast offense (which is generally built around a short, scripted passing game that favors good route runners with good hands).