This game has lost an awful lot of it's appeal, at least for me. Yes, true, the game is not made for ME, it's made for the masses but I really think there are a lot of peeps that feel the same as I do. (Just as there are elite vets that will not agree also. These are just my opinions)
1. Killed the rush. In D2, and at first in MedianXL if someone wanted to get to 99 quickly, you could get a boost within a couple hours and begin the 'interesting' part of the game. (Cows, Baal run, etc) Nobody cares about the 3'rd (100'th?) time in a season you free Cain or take on the ancients on the mountaintop. It's just the boring slog to get to the rest of the game. So hey, I know, let's take away the speediness of it and force everyone, every single character to HAVE to play through it all 3 times in a row, over and over again. Blah. Done with that.
2. Killed the OP. As others have stated, once you HAVE dragged your butt through the 3 levels of the SAME game, you can farm Duncraig and Fauztinville, etc for that (Maybe) 1 Su per run. A few seasons back, I finally had a character (Necro with the Hwanin's Hwacha specific build) that was FUN! Killing everything on the screen quickly and picking up the loot IS the point of the game. So... Lets Nerf that shiz baby! This has reduced the fun on several of the characters that used to be fun at one point or another. OP kicking ass of mobs IS what makes it fun! Why not allow 1 OP weapon or specif build PER character class for doing power-farming, then peeps can experiment with the gear that drops to do other builds.
3. Blocking areas by level. Ok, understandable that you can't get into somewhere to get a quest item that requires level 105, etc. Why get a 105 charm if only a level 85... Fine. But keeping people from being able to wander the cow zone looking for scraps, or craftables, or even just piles of gold etc just sucks.
4. Making some bosses simply impossible to kill with a character class.
I know there are veterans of the game that will say "lern the game mo betterrr man". True! But I don't want to put hours and hours of time, building up a fire sorc, lightning sorc, bowzon, etc, just to find out that they CANNOT take down XX boss without calling a pally buddy in to kill them for me. Or yes, I CAN make my way through Duncraig to get my 1 SU (Maybe) but I die 5-10 times in process.
I've followed numerous character guides but I strongly believe those guides are used by the Developers to outline the next nerf list which is why there are VERY likely builds (With fighting technique) that will NOT be written, as the players that HAVE figured something out want to make damn sure their fav doesn't get smooshed down in the next release. There are many high level areas of the game that I've not even messed with because getting the exact right gear and slogging through just isn't really worth it, especially when it doesn't perform as advertised because I missed the little message 28 pages in that says (This build sux now due to xx nerf)