Even I'd argue that you'd have to take the potential results with a pinch of salt though.
We all know and accept that the Dutch league isn't the best (currently ranked 7th out of top flight Euro leagues behind both Ligue 1 & Portuguese Liga), so a possible hatful of goals has to be tempered against this knowledge.
However, if it can be clearly seen that the system Vitesse are using is designed to get the best from RvW and thusly his goalscoring goes back to previous levels, I think it would be fair to say that this is an incredibly strong indication that we (and to some extent St.Etienne & definitely Betis), simply didn't correctly utilise the player, and that had we done so, we would likely have seen a far better goal return than we did.
This doesn't mean that he'd have finished with the golden boot, or that we'd have walked the league, or anything along similar lines, but a simple vindication that he IS a good player, that he can pose a very dangerous and genuine goal threat, and that we just used him totally wrong which lead to the 3 year saga that did nothing for us - or him....