Though an unintended consequence of the English Wittelsbachs might be a stronger Monarchy. After all the early Hanovers needed Prime Ministers because they didn't understand English law and customs and, for George I, didn't speak English. Those problems wouldn't exist here.
I had wondered about that point, but OTOH the rising importance of Parliament & the Ministers actually seems to have begun under Anne (who apparently wasn't very interested in the details, as long as her own favourites were favoured, although admittedly there was her use of the veto on one occasion) if not William III (with his attention partly focussed on his Dutch interests, instead) rather than just under George I... and Rupert had seen first-hand in the ECW what a serious disagreement between King and Parliament could lead to, and might have taught his child[ren] to be wary about proovking more such trouble. I'd expect a slightly stronger monarchy
if Rupert's heir had inherited much of his intelligence, but probably not attempts to exert the level of royal control to which the first four Stuart kings of England//GB had aspired.
There's another potential line of Wittelsbach succession, too. Rupert's younger brother Maurice also came to England, and fought for the Crown during the ECW, but died from illness while taking part in a naval expedition (under Rupert's command) during that period. If
he had lived too, then marriage and an heir might not have been beyond the bounds of possibility for him.