Shadow, this has been going on for a while now, Caste stooges like McElroy projecting athletic, running white quarterbacks as tight ends. As much as I dislike Greg as an analyst, remember before Taysom MOST athletic white quarterback's moved to tight end. Unfortunately that's how NFL does business -- racial stacking.
Heck, before (and after) the Jaguars selected Matt Jones in round one as a wide receiver most "draft experts" slotted him at tight end....Tim Tebow never got a shot at tailback, power back. Could he have been a LaGarrett Blount type? I thought so. He only got a brief look at H-Back and punt protector with the Caste Jets.
Less often smaller quarterbacks are moved to slot receiver (i.e. Julian Edleman). Any one else remember how the Rams tried to move mobile Heisman Trophy winner Eric Crouch to receiver after picking him in round 3? When asked by St. Louis media why he couldn't play tailback, the Rams' black RB coach said he's "too small", which is bizarre, considering several hundred blacks much smaller than Crouch have played tailback in the NFL since the 1970 merger. Crouch refused to move from quarterback and retired. After he decided he needed cash, he tried to come back as a safety with the Packers after a stint with Hamburg (NFL Europe).
Speaking of quarterbacks moving to safety, I recall vividly from the mid-90's, into the 2000's, many teams were looking for their own, modern day Nolan Cromwell. So we saw goys like Scott Frost drafted as a safety (3rd round Jets)....Rams also picked an Ohio State quarterback (Steve Bellisari?) and moved him to safety. Sure there where others I don't remember. But moving athletic college quarterback's to safety is now unacceptable in the NFL. Edleman was probably the last, and he only dabbled at CB.
Most quarterback's failed after the move to receiver, particularly at tight end, due to issues you brought up -- size, blocking, never caught a ball, ect. Hopefully the new trend is towards Taysom types going forward -- let them run the ball. It's not rocket science, it's just a man running forward with a ball in his hand trying to advance it as far as he can. Why all the racial machinations?