I don't think KT unclogs anything personally, one of the rare times we disagree, Supa.
Our leading receivers last week had 97 and 24 yards, with a TE and RB in between. KT has been a serviceable receiver in the past but, he's not suddenly going to provide another dimension over Amendola that fills the LaFell void, regardless of which WR position he plays.
I don't even know if it's an advantage, but the biggest thing that I liked about KT is that he came down with contested balls at times, 2013 vs Falcons and Saints for example. Harper hasn't really played NFL talent in that aspect, so who knows.
For this specific game I might prefer to see Jonas Gray (knows the scheme) brought back since Miami released him, Bryce Brown for gamesmanship, or a FB for help on the OL front.
I don't think a WR worse than DA provides anything to the offense, against Buffalo's front 7 we need a good pass protection or quick-strike type route combination offense, the intermediate passing game doesn't generally help in this one. Might be the kind of game where TB12 wants the ball out under or around 2 seconds each snap.