He's not a bust yet, way too early for that. I do see him as a bit of disappointment considering where he was drafted, but then again, his draft position is not his fault and even back at the time we knew that it wasn't a very strong draft at the top. In fact, things have played out pretty much as we expected them too back then. Of the three options we had (Reinhart, Bennett, Draisaitl), Rein was the safe one with not a lot of flash but a very low floor, and that's exactly how things have been going for him so far. Draisaitl was the boom-or-bust pick of the three and he has turned out great, but while I would've loved to get him back then for the German-factor alone, he was the riskier of the picks and who knows how he would've developed had he been in the trainwreck that was our organisation these last few years instead of in Edmonton. And for Bennett, his strong start seems to cloud some peoples judgement because since then, Reinhart has arguably been the better and more effective player.
So yes, I am a bit disappointed Reinhart's impact so far, but he is still young and far from a finished product and he also is pretty much the player that he was advertised as back at the draft. Calling someone a "bust" this early is usually based on the expectations you had, and I'd argue that if you call Reinhart a bust at this point then it's because you had the wrong/overblown expectations in the first place. He will never be a dominating 1st line C, but he was never advertised as one either.