Jay Cutler was brought in as a one year stop gap in a failed year. Tannehill had gotten injured and it was basically accepted at that point the year was wasted. He didn't do anything bad by any means (well relatively speaking), but that was also the beginning of the end of the locker room cohesion and he sure didn't put out any fires.
I think Phillip Wheeler gets forgotten because he was one of about 30,000 moves that offseason that completely backfired. Dion Jordan, Dannell Ellerbe, Mike Wallace, Tyson Clabo, and how easily we forget Dustin Keller.
Brandon Marshall is an interesting one because he cost us two 2nd rounders. I believe we got two 3rd rounders from Chicago, but still. Everything about that experiment was failed and he torched every bridge on the way out. I remember after acquiring him I thought we were set up pretty good, and basically the next day we ship out Ted Ginn Jr for pennies. Never understood that subsequent move but that was Jeff Ireland for ya. Fill a hole create a hole. Offense had no speed that year and defenses just sat down on everything including the run game. Trusting Brian Hartline to be a number 2 receiver was a bad move and we repeated it for like 5 straight years. I think we tried to fill the speed gap next year with Clyde Gates, maybe he caught 4 passes in his career.
The problem with saying Brandon Marshall is how different would that acquisition have gone if we had managed to sign Peyton Manning in 2012? I think the Brandon Marshall era goes very differently with Manning at QB. That would be why I'm hesitant to say it was the worst signing since Henne was the real reason those two years were disasters.
Worst signing has to be Mike Wallace. Brandon Marshall was at least a good football player before and after the Dolphins. Mike Wallace was a locker room cancer who demanded the ball be fed to him. He turned 141 targets into less than 1,000 yards his first year. Set this team back.
It's notable how many of these awful moves were made by Ireland. Man he wasted those Wake, Starks and crew defenses.