Honestly ,I played a little Diablo in the start but when D2 rolled out I played it exclusively for 15+ years with breaks here and there all the way up till D3 rolled out .Even then I would go back and play mostly when I got bored of seasons. The only thing I actually found difficult was getting those first drops because back then most people like myself were all beginners at this. Once you actually understand the game it is actually just about playing even casually which I did for a long while . You could still jump right in and with in a few days have either through Drops,trading or just free stuff games have a hell capable Char. and be soloing if you wanted to or just joining random pubs with the ability to at the very least not die and get even more drops from Pre .10 cow games or post .10 Baal runs. Hell,Just Killing Shenk will get you some really good drops and he is perhaps the simplest “Mini boss” in the game at 30 second runs .
The only thing “hard” about D2 is having a little patience and spending a bit of mind numbing time doing Magic Find /Loot Drop runs. Other wise this game is really a cake walk.