Not necessarily disagreeing Alen how good he is (I want him signed too), but there are two important factors I counted in. Firstly he is playing in smaller team, expectations and standard of play is different there from in a top team. Been many players who impressed there who cant quite cut it with a top team (the almirons, tavano's and even Gila). Being amazing for one and the other is different. Also he has so far only played a half a season. Many can have stellar half seasons. Its counting your chicks to early if you already consider him the top best in the league...
One needs to prove and show a bit more then that, for sure. Not much to go by consistency wise. He isnt better then Montolivo as a talent at all, but having a better half season. Montolivo is exactly the type I mentionned in my earlier post, extremely good talent who needs a breakthrough, shows immense impact now and then but is not ready yet and not shown consistency. He has earlier in his career impressed big time as Hamsik is so far in half a season, but then later on struggled to keep that form, hence not really have had his breakthrough yet (and Viola is for sure better and demands more then Napoli does). It would be good if he could keep up stellar form all the time, then he would be an almost top player, but he can also be like the most majority of top talents who struggle to keep at it and just not hit that top level just yet. Not be as consistent as a top player needs to be.
In the end, its all about perspective, and expectation. If you decide a good half season is enough to call Hamsik a proven player, IMO its not because lots of other quality talents has had those kinda big moments only not to maintain it later on.