I don't have enough time for a long post so here is a short version:
If you didn't like the demo, it's very, very likely you aint gonna like the game. Art is bad, and i don't mean the graphics. The original Diablo had a much better feel. Deathknight looks retarded. I wish there were some options there. "Tactical" combat sucks. I tried the battlefields: fucking boring. Four or so stripes of land with dungeons in the middle. I went into the first dungeon, everything looks the same, and has the same monsters (lvl 2 skeletons), but truckloads of them. Then I reached the dungeon boss, who was lvl 12, and killed him easily. He was tough, but I had plenty of potions that restore health instantly unlike D2 ones, so that was boring. A few quests that I encountered on my way were boring as well, typical fedex stuff. There are bugs: one dungeon is empty, and my small hammer (one-handed, crashing) doesn't get any bonuses from one handed crashing skill. Some items do, some don't. The skill system is ok, but nothing special.
Well, like I said, I hope I missed something or was very, very close to something fun and cool, but went to investigate the battlefileds instead and got really turned off.