i had the opposite experience, i loved D3 so much (after Reaper of Souls released) that i just could not even begin to get into D2R. the itemization in D2 is so dated and horrible, finding gear for your build is way too hard making it deeply unsatisfying. also +skills just is not interesting. levels on skills at all is not interesting, nor is locking you into choices you made while leveling. leveling should be used to experiment and not be penalized for that. it feels a lot more restrictive gameplay wise because you'll typically build yourself around a single ability you spam constantly, whereas D3 forces 6 abilities, a lot of times you're gonna have passives there and some builds are absolutely built around spamming the same thing endlessly (i avoid those builds like the plague, they literally put me to sleep), but i still found it a lot more engaging and less passive.
also shared loot is a dealbreaker in this day and age. that alone made it so i would not play online which is the biggest draw of this type of game, cooperative multiplayer. if it's local that's fine, but online? no way. people hoover up all the loot so melee classes have a hidden +stat to steal all the loot and then state that it's for their alts.