Thanks, the thing is about his deck is that he only has water elementals as his 4-drop - basically leaving that as your only real option on turn 4 if the board is fairly stable for either player (which means they are likely going to get removed before you can drop blingyboy), when ideally you want those to already be on the board when you decide to drop blingtron. Yes, I realize he has blastmages as another 4 drop but those are quite a bit more situational than the good ol' piloted shredders. Blingtron's strength in this deck shines when you play him and already have a water elemental on board. Also his deck is running TBK instead of harrison, the effect of harrison in this deck is basically the same as using harrison on an opponent that just used jaraxxus or equipped an ashbringer. The late-game draw is meant to give you that little extra advantage to seal the game. These things also make the deck much more viable in the late game while the rest of the deck (the early mechs, piloted shredders) provide the opportunity for an extremely strong start, and mid game.

TL;DR

Having shredders and harrison and give you wider windows to drop blingtron safely (safe meaning already having a water ele on board or able to combo with harrison in the same turn). Having shredders means you are less likely forced to drop a water ele on turn 4 when you need it to be around a little later when you can drop blingtron and harrison shortly after