i do happen to like white a great deal... just not quite as much as bush, especially in a PPR league...
as to whether they are system guys...
i believe that if you put deangelo williams, lawrence maroney or adrian peterson behind the USC OL & embedded in that system last few seasons, they put up very good stats as well...
but the converse is true as well, imo...
if bush plays for a respectable div I team he probably takes a run at 2,000 yards if he doesn't divide carries... white also could have been the full time starter for just about any other team in the nation & might have had 2,000 yards & 40 TDs in a full time role... we don't know for sure if they could have handled workload (which is question about both, perhaps more about bush as some question his stature, though some question white's conditioning, stamina & endurance)...
one way i look at it is, independent scouts like mike mayock who himself played the pro game, are supposed to isolate out the attributes of a prospect & imagine how they would do in ANY system... some of those guys insist bush might be the best college player they have seen in 20 years, & he is one of the best RB prospects ever... you have to assume they are aware that he played on a team that also had first rounder leinart, mike williams, possible future first rounder duane jarrett, second round OL like latui, etc... & they are taking that into account.
USC has had some pretty good RBs over the years, maybe different systems, different coaches, but RBs like OJ simpson & marcus allen had a lot of success in the NFL... white was first freshman to ever lead team in rushing, tied the conference record for rushing TDs in a season & broke USC mark, broke the school & conference career rushing TD mark... white is good...
just not sure if that bears on whether bush is or isn't worthy of starting as a RB2 week one?
i watched a few USC games in recent seasons, but i don't recall if there were a lot of situations where bush & white were on the field together... i think it was often one or the other... i expect payton to get the ball in bush's hands a lot this season, & since he has WR skills, i think he will be on the field WITH deuce a lot... there will be times when bush may get a reception in that configuration, rather than deuce getting the carry...
i think with the way he divided action with white at USC, that situation was more of a either-or situation... which might make it difficult to project what he might do in new role based on old one, as they may be quite different.
* to cite some context-INDEPENDENT examples of things that might suggest bush & white would have been monsters in ANY system...
on some of bush's runs, & there were numerous examples, he was weaving through defenders WITH NO BLOCKERS!

no doubt the field was spread with all their weapons, but when three guys are about as close as a phone booth & nobody lays a hand on him, i can't help but think that reflects positively on his ability...
watching white run, he showed a lot of patience, vision, instincts & quick feet to hit the right hole... based on many rookie RBs i have seen in the past, few had those abilities to such an advanced & mature level of development... imo, they unmistakably bode well for his future in NFL... there were also times, like when he threw michael huff to the ground in championship game, where huff wasn't blocked... that was a one-on-one matchup he dominated, & didn't necessarily have a lot to do with the fact that he was behind great OL or had masterful play caller...
this gets back ISOLATING their attributes independently from a specific context they may have happened to be situated in at that time... that is what scouting is...
check out bush's workout... it was one of the best ever (maybe THE best) for a frontline RB prospect of his caliber... that clearly has little to do with who he played with last three seasons...