Thanks. None of that really makes any sense to me. Link an in depth article if you don't mind and have one handy. I'm not looking to defend D3 or anything, I've just never felt the chasm that other people have between the two and I think I need it spelled out for me.
I probably spent 10 hours playing D2 online and maybe 30 hours for D3, so not much experience.
I don't have any articles to back that up, it is just my own opinion. I put at least 500 hours into each and probably twice that into Diablo 2 and D3 feels like they tried to make everything from D2 friendlier without realizing that it made the game worse.
Skill trees - Diablo 2 had branching skill trees that rewarded players for either investing points into single skills to make them more powerful or branching into more powerful skills deeper in the tree with less investment. There were multiple trees for every class so you could really make some wild builds. In a later patch they made points in some skills give bonuses to other related skills (i.e. every point spend in Fire Nova gives +1% damage to Fireball).
D3 had none of that fun, you get skills at predetermined levels and later on gear can make them better.
Skill choices matter - There was no refunds on skills so you had to choose wisely and the internet didn't have many popular best build sites so you really had to figure it out. However, the game was easy to restart and leveling to a decent level was not hard so the process did not feel as burdensome.
D3 thought making skill choices interchangeable and not matter would mean that no one would need to relevel another character, but in doing so made the skills bland and...interchangeable. Also, a huge part of the replayability was then gone because there was no reason to grind up more characters once you did one of each.
Rune words - This is more that Diablo 2 introduced sockets and then in the expansion introduced a way to make sockets matter in new and interesting ways. I also want to mention Charms were a huge and cool thing that was added in the expansion that really changed the way the game was played and opened up new builds.
D3 actually regressed in this area by not finding a cool way to include charms, eliminating rune words, and makes sockets pretty much a requisite instead of a trade off that was good in some cases and bad in others. They "streamlined" the game by taking away player choice and making items bland.
Item types - Diablo 2 pioneered the formula that the more hybrid an item became the lower the stat cap could be. Blue items had less mods but the mods could go higher than yellows or uniques. Uniques sometimes broke this rule, but most had stats not found on any blue/yellow and almost always had downsides. This made some builds actually covet lower tier items and made farming that much more enjoyable because blues were not just throw away items. Hell, sockets only appeared on white items and that made them some of the most sought after items in the game. Set items were released in the expansion and, again, were not the be all end all but gave players a reason to gamble and some different choices.
D3 threw this all away with an item system built around the Real Money Auction House and now we are at a place where the best items are clearly a few uniques and the set items. The set item skill bonuses along with the boring skill tree makes a few builds the 'best' options bar none and reduces player choice to almost nil.
Targeted farming - In Diablo 2 there were many farming spots that you could run for items depending on your build. If you wanted Runes you ran the Countess, if you were a teleport Sorceress you ran Mephisto, non-teleport builds would run the Council. If you had freeze immunity or the freeze immune boots you could run the Slug Boss. Poison resist could run Andariel. The result was even more build options focused around farming specific content to acquire the items for better farming.
D3 started with bosses giving a *slightly* higher drop table than other enemies but rerunning the boss would cause the in-game cutscenes to kick off every fight which made them last FOREVER. This oversight made it so that boss running was worthless and the most valuable money/MF builds were simply as much item find as possible on a fast character to
break vases and open treasure chests since destructible items were easier to "kill" than mobs. They didn't want farming because they wanted to pimp the RMAH as the way to get gear and it broke their game such that now you are farming and gambling for the one set of items that is best for your class.
These are all problems that I glossed over because I wanted a new Diablo game so badly that I was OK with whatever I got. I played it a ton so it isn't like I hated D3, but the points I laid out are why D3 will never be considered a classic like D2 is and why now that I invested some time into PoE I realize that I wouldn't have played D3 more than a few hours before realizing that PoE is the true D2 sequel that I wanted. If you like D3 then great, but it is not the game for me and with the new Blizzard philosopy there is a 99.9% chance that D4 will not be either.