Sure, it's totally fair to say that RF brings some new stuff that EF never had, and won't ever have. But if an EF lens on an EOS R works as well as an EF lens on a DSLR EOS, then one should not criticize the RF mount or EF to RF at is adapter's technical ability, because if Canon had made their first mirrorless an EF, it wouldn't have that new stuff either. In other words, the EF lenses will work as well as the lenses were designed to work.
I would be really surprised if the lens itself provided core functionality that I thought was must-have, mostly because I didn't fall in love with Sony glass, even the high end GM lenses. But we'll see, and obviously, a lot of it is also what Canon decides to make. If they make more interesting stuff like the 28-70/2, that would sure help nudge me to spending money -- not necessarily because I want RF features, but because I want the optics, and that's the only way I can get them.
And I guess, finally, the verdict is not in yet as to whether native RF lenses are in any way superior to EF lenses in the basic tasks, for example, autofocus speed -- or if the new stuff those extra pins offer is simply for new features. If it's the latter, then the question becomes, a simple question of for lens X is it worth switching? At least for the perceivable future, my DSLRs aren't going anywhere, so the EF lenses can work on both systems (if I buy an EOS R, but who am I kidding, if I don't buy this one, it's only because I'm holding out for the next, "more pro" model), so are the RF benefits, one of which would be no adapter, be worth that.