I'm not particularly interested in whether or not a guy makes an all star team or not. It only matters how he plays. IT could play very well and fail to make the all star team if some other guards have great seasons. I would not consider that a failure on his part.
I think of the situation this way, it is fair to assume that Kyrie will play at a high level. He has been consistently excellent as an offensive player (and bad defensively) and I see no compelling reason to think that will change. He is also younger, taller, and has a better contract situation than IT.
IT played at that very high level last year, but has not done so consistently. It is of course true that teams were reluctant to give him the opportunity he needed to excel, and once he got a chance in Boston he took it. It is a fact, however, that he has not played at the highest level throughout his career. I'm not saying he was trash, he was good his first full year in Boston and he played well his last year in Sac, but he has only reached Kyrie's level once in his career. Couple that with the injury and there is legitimate reason to wonder how good he will be going forward. If healthy I'm sure he will play well, but how well we don't know.
The pick could end up being a great player, or it could end up being a bust, there's too much uncertainly surrounding that to know for sure. The Cavs have added pieces that could potentially have much more value than Kyrie, but could also leave them will not much.