Unless you're arguing that old BG fans want only the mechanics and game features that were in BG 1&2 and no more, which is such an incredible strawman that there's not much more to say.
Whilst I take your broader point, I have seen old BG fans arguing exactly that. Had an entire Youtube comment argument with someone claiming that a Baldur's Gate game shouldn't call itself Baldurs Gate unless it's RTWP...