Okay, got your point, I'll rephrase a little - all three of them could be highly rated and in 5 years time for example Portanova could explode massively and reach world class status, who knows? At this moment though, so far I would say that from all three of them Rovella has the biggest chance to ever play for Juventus and be a part of the first team, be it as a squad player or even important first team regular, again who knows? I guess that's pretty much what the board thinks too, so swapping two players that won't play for the club with one that might or have a bigger chance to play is fine by me, it makes sense.
I would agree with you completely if those were the only two youngsters that could generate funds for us and should have been used in a different deals, but that's not exactly true. They are not the only two youngsters, for Locatelli for example we could use what the media reports - Frabotta and/or Faggioli, and for a third player we could use another two players from Under23 side or lower, which is basically the point of having a B side, to use youngsters as assets to sweeten a deal for a greater potential. Let's not kid ourselves, we are obviously not going to produce a wonderkid and a world-class player on our own any time soon, we simply don't do that, so exchanging few of them for someone highly regarded seems fine and logical to me, not every youngster we get that way would turn out to be a world-beater but few of them would, eventually, it might or might not be Rovella, but few would, I am sure of that.
Bonuses are fine by me, most of them are performance based, if he manages to fight and earn his spot that would mean he is good enough to command a spot in Juves starting 11, I look at the bonuses from a different angle, I hope Juve ends up paying all of the bonus feeds which would suggest that Rovella covers all the performance criteria that was required and requested, if he hits the ground running and turns into a beast those bonuses are peanuts, if he fails miserably then he simply won't cover the parameters the clubs agreed and Juve won't pay some or even most of that 20 mil...
That plusvalenza shit is on the thin line between legal and illegal, I don't like it much either but this is what the clubs do nowadays, I hear they are planning to remove the financial fair play for some time so if that is the way the modern football is going then plusvalenza deals are here to stay and be part of any top club mercato strategy...