I'm not ready to call him a bust just yet. I was impressed with him his rookie year. This season, I don't know if you want to call it the sophomore slump or what, but there were a lot more noticeable mistakes made by him. Some of that was from injuries in the D group forcing him and Barbs to play more minutes and in harder situations than he did the year before. That was something he did not look like he could handle well and be completely comfortable doing at this point in his career.
I'm holding off calling him a bust though because I think you need a lot of patience with him. Defensemen typically take longer to develop. When Sustr signed here he was regarded as a late bloomer, as it probably took him time to grow into his 6'8" body, and a raw prospect. He's still somewhat inexperienced. When you compare him to Barbs and Gudas, both those guys had a lot more pro experience and had of a lot of time well spent in the AHL honing their skills and developing at a more suitable speed. Looking at Gudas specifically, he already had already spent 206 AHL regular season games, 34 AHL playoff games, and 22 NHL games before the start of the 2013-2014 NHL season, while Sustr only had the time he had spent with Syracuse after signing with us which was 26 games.
So hopefully what you see now is not the end product and with time he'll be better.