The risk with Amorim is that if you make a big commitment to him, shipping out players that don't fit his system and bringing in players that do, and he doesn't work out, most coaches aren't going to be fits after he leaves and you're going to have to "start from scratch" again. Obviously some players can fit a 3-4-3 or a 4-2-3-1 or a 4-4-2 or whatever, but some players are definitely more specialists.
That said, if it works, who cares? And you have to give Amorim enough time to make it work IMO.