Unlike others, Gallinari is proven.
Proven Euro players who produce in competitive leagues and are on winning teams proved to be successful NBA players. That is fact, you should do your research so you could know who those players are. Every good international NBA player produced in a competitive league on a winning team. Gallinari done that in a different level at 19 and basically had a Lebron James type impact in Europe. That what makes him so special.
Young Euros who don't get minutes in Europe and are drafted on projections turn out to be bust (Darko, Nicoloz, etc)
Weis actually isn't a bad player; he just decided to stay in Europe.