Sanctuary
Member
It basically started this genre of games.
Just a few points as to why the game is a classic:
*Purely randomized content that leads to increased replayability
*Deep customization/skillsets among the various classes
*Phenomenal loot and item system allowing you to spec characters in a lot of ways
*Great dark atmosphere and art design
*Solid lore, classical sound track
*Excellent online features for the time including stuff like Ladders
What always had me coming back for more (initially) aside from the random items was the build learning process. It seems like today, some people "don't have the time" (even though they will spend 100+ hours playing said game) for making a character only to find out it's not 100% optimal, forcing them to have to start a new character of that same class all over again. In the earlier days, experimentation is what made the game so endearing, and after you failed once or twice, you should have had an understanding of what to do or not to do. I loved having classes that were dedicated to specific skills, because they played so different from another and also gave you a reason to play the same class multiple times. Diablo 3 doesn't have that yet.
Sure, one can bring up the argument for cookie-cutter "optimal" builds, but that didn't really exist nearly as much in the early days. Yeah, some skills were obviously those you'd want to pick over others, but the game had enough skills that didn't totally suck that allowed for variant builds (Remember the Singer Barb in CD2? Awesome and fun, yet entirely niche for a long while) and the entire building process to see if it worked was often the carrot at the end of the stick for me. Then when they introduced synergies, it helped the build diversity even more for a while. Diablo 2 had many builds per class that worked very well in multiplayer in Hell difficulty. Diablo 3 seems to only have 2-3 builds per class (tops) that perform good to great and there's really no room for experimentation. You do that while leveling, or at 60 for a few hours until you realize that most of the skills are simply lacking.
I haven't played it and I probably won't, but from all I've read or watched, Path of Exile is the closest one can get today to the Diablo 2 experience.
edit: This game is becoming almost completely unplayable on the PS3 now. I just had my fourth save error (third in only 24 hours). Something is happening while the game is saving so that it acts like you've never played the game and it saves it as that state, even if your save file shows characters on it. Backing up saves doesn't really matter except to prevent huge amounts of lost time, but for short term sessions it's a complete crapshot whether or not you'll lose all of your things. You also have to make sure that the last time the system tried to save your game that it actually loads before trying to save it to the USB, or you just end up with a screwed up save that won't do anything for you as a backup.