I have two main reasons that I hate LDoN... Dungeon Crawl and Chucky Cheese prize booth.
First off, I really dislike dungeon crawls. I prefer sitting in one "camp" and killing mobs. The traditional old school EQ grind isn't for everyone, but it is what I like to do when I play EverQuest. I have numerous other games I play when I want to crawl a dungeon. To me, EQ is about grinding mobs in a camp and socializing with your group members. LDoN destroys that completely.
Secondly, I hate hate hate hate HATE the Chucky Cheese prize booth game design that LDoN introduced to the industry. It's lazy game design that makes dungeons irrelevant and lack luster. WoW took the idea of "run through dungeon, kill boss, collect points, spend points for gear at the prize booth back in town" to the next level of stupid, but EverQuest gets credit for introducing the idea in LDoN. LDoN"s Chucky Cheese prize booth design was the begining of the end for traditional MMORPGs that had meaningful dungeon design with rare mobs and rare loot.
LDoN could have been a great thing IF they would have made large meaningful dungeons with rare mobs that drop rare and extremely-rare chase loot that had camps and respawning. That way, your group could get their own instance of said dungeon, and camp it for x number of hours. That would have been great. Instead they got private instances with no respawning mobs, forced dungeon crawling, and lack luster rare mobs because the real loot was obtained by collecting points for doing the instance runs and using those points back in town at the prize booth for gear. Seriously. LDoN was the downfall of the MMORPG industry.