I don't think Rossi should have been disqualified at LS 2008. What should have happened, seems to be the rule in motogp now, and has usually been the case in most forms of motorsport, is that he should have been required to give back a place that he had gained or kept (the latter is what Rossi did at the corkscrew back then) by going off the track. It wasn't at all clear, however, iirc that there was such a general or local rule which applied to the Corkscrew incident back then. My consistent view in regard to the incident is that Stoner had very adequate grounds for being annoyed, in that it was a riding error that nearly resulted in him being torpedoed through no error of his when in control of his bike on the racing line. I also don't think he was thrilled about nearly being forced off the track, again when on the racing line, on the lead-up to the Corkscrew. I disagree with little Walter that attitudes have changed to that incident, and whether or not this forum is a "Rossi Haters Forum" I think many other forums are much more on Rossi's side in regard to recent events. What those events do throw into sharp relief for me is the hypocrisy of Rossi fans and perhaps Rossi himself in view of their attitudes to the corkscrew LS 08 thing, and in particular Stoner's characterisation as a whinger/whiner; any whinging by Stoner back then has been vastly eclipsed.
I don't disagree with RD's decision in regard to Assen 2015, even though watching live I wanted MM to win the race to help JL's championship bid. Perhaps it was humiliating for MM that Rossi apparently outsmarted and anticipated him, and moved in advance of more substantial contact, but there was no way imo that MM was making that corner at that speed and on that trajectory without forcing Rossi off the track or torpedoing him if he didn't move. MM perhaps had reason to believe such a move was legitimate though, since RD allowed his move on JL at Jerez 2013, and the Assen incident does provide evidence imo for J4rn0's contention on the "Untouchables" thread.
My poor choice of words. Yes quite correct that giving back the place gained is the traditional remedy. I have seen racers do this of their own accord. Not sure how this gets done in these circumstances. Black flag come in for a stop and go? Or wait until the end of the race? All messy choices.