D4 is an objectively terrible gaming experience. This is also a d2r discussion forum..
D4 is also coming out with the Warlock, who looks much better than the D2R's counterpart.
Although D2R remains dearly in my heart (I played this through the AOL internet connection 56k modem) and it remains one of the classics that really forged the way for other ARPGs, it is just an outdated game at this point.
Can you still play it? Yes. Can you have fun with? Yes! But is D4 is superior in every way? Not quite, but in my opinion, it's probably better in areas that I think are important.
Not all love D2, and not all love D4. But each is its own, and I respect different people's tastes.
In conclusion, I don't think D4 is an "objectively terrible gaming experience" because clearly, some enjoy it.