I'm not making a player to player comparison for Travis to Percy but more from a developmental point of view. To me Percy and Dermott are similar prospects at the same age. Both probably 2nd pairing Puck moving dependable D men with limited offensive upside.
I recall when Percy was drafted, people were similarly high on him at the time citing his hockey IQ. I thought he would be in the NHL once he completed his OHL career due to this, certainly after a short stint in the AHL, I am still surprised he is still in the AHL today.
But anyway, this is where I see the similarity. It will be interesting to watch Dermott's progression, where I think Nielsen has passed him on the depth chart, as he has progressed faster.
Further, I do agree with you on the premise you brought up. Seeing the potential players Leafs passed on to drop down, it may be a possible miscalculation. Only time will tell for this. This is okay to admit as a fan, as you are one of the few that can see not only positive outcomes but negative outcomes. So I commend you for atleast asking the question on the Main board.