So, since this is apparently supposed to be restricted to what I hate about the Realms...
I hate that starting as early as 2e they started dumping any and every "cool idea" into the Realms. It greatly diluted the feel of the setting, and only got worse as time went on. Every supplement in 3.x had new races and classes. Some of the classes were OK, but the races just get annoying because adding another intelligent race to the mix and pretending that it always existed alters the relations and relationships of the cultures, politics, etc.
4e, of course, went much, much farther. I could handle the Spellplague (seems appropriate enough for what the Realms had become), but didn't like the jump forward 100 years. Floating islands and stuff was OK, but returned Abeir was wrong on so many levels. Reworking the planes and the gods to match all the core of 4e was a big miss. Oh, and the big holes in the ground and the other changes in geography. And eladrin. How I hate eladrin. And dragonborn. And tieflings.
Many of the novels suck. Poor writing, poor stories, very poor adherence to the physics and nature of a D&D world, and too many epic "save the world" adventures. There are some gems out there, but the glut of mediocrity wasn't limited to the supplements.
Sembia. In the OGB it was specifically stated they would never populate or describe Sembia besides the outline in the OGB because it was left for the DMs home campaign. And then it wasn't. Perhaps it was too close to Cormyr and the Dalelands to leave untouched?
The changing geography in general. The 4e changes were one thing. But the 3e map rearranged things to fit on one page, and condensed them so travel distances were all screwed up.
Too many reprints. Much (50%+?) of the material in 3e was 1e + Volo's Guides reprinted. The 2e stuff was mostly cut and paste from the 1e stuff. I get that it needed to be updated to the new rules, but one of the advantages of the FR supplements in 1e is that there isn't a whole lot of crunch. So most of the fluff has been printed at least 3 times. Waterdeep more than that probably.
Too many cooks. This isn't a problem relegated to the Realms. Lots of people came and went at TSR, and of course there was the move to WotC. But Greenwood has always been available, and writes prolifically (more like vomits forth lore copiously). I'm sure there was stuff to deal with contracts, and such. But that was a huge miss in my book.
Reworking the Realms as the default setting. I had forgotten that when 3e came out, Greyhawk was the default setting again. Well, it was never the official default setting, but since AD&D was Gygax, everything matched his world at the time. I just think Greyhawk makes the better default (I won't say generic) setting because of that. Had they maintained that, perhaps 4e wouldn't have screwed up the Realms so much.
Inconsistency in presentations. I like things like different currencies for different countries, regions, city-states, etc. It makes sense to me. Ancient coins lie in ancient tombs. That sort of thing. They were/are very inconsistent about those sorts of things over the years. This is another problem in D&D publications as a whole, where they haven't maintained a consistent presentation within an edition. So if you're going to list the coins of a given realm in one supplement, do it for the realms in another supplement.
Every damn thing in the 4e FRPG. No wait, there's a picture on pg. 48 that I love. Probably a couple of others.
Arcane Age. And Under Illefarn. Under Illefarn was released before the OGB if I recall. They provided information for the rulership of Daggerford. Conan and Sonja. Really. The supplement was pretty good, but that was just absurd. The Netheril box set (part of Arcane Age), had silly names and a lot of poor writing. The idea is that the past was a period of much greater magic (10th level and greater spells!), and that many of the dungeons found today are from that era. A real wasted opportunity.
The Horde. Maztica. Anything to do with Spelljammer in FR.
Anauroch is both amazingly cool, and a lost opportunity dumping the Bedine in there (although a greenwood written supplement, I'm still convinced he was told to do the Bedine). The coverage of the culture is really good, but has no business there. If anything it would have worked OK in Raurin.
I'm on the fence with Old Empires. The use of Egyptian gods could have been a decent starting point, but it's too incongruous. The cultures are pretty cool, and the idea of a land where the gods are native to the prime plane and rule the countries works for me too.
The Complete series of books specifically for the Realms. So much junk, with perhaps a few decent things. I forget. I'll have to dig them out and see how much they bum me out.
Moonshaes. I don't think Ed's Moonshaes were a copy of the British Isles. I'm pretty sure that the novels and the future supplement were tacked on. With so much material to work with right at the beginning, why did they feel the need to tack on so many non-Greenwood things.
Too many gods. Some of them were added by others. Some I'm OK with, after changing some of the dogma and such, like Oghma and Deneir.
The 5e lore. Here we go again. Tons of stuff I can't absolutely stand in VGtM. The background of SKT. The fact that within 3 years we've apparently saved the world from Tiamat, all of the Demon Princes, a transplanted Greyhawk theme, and all of the giants. Having said that, and despite it being another Greyhawk inspired transplant, I'm looking forward to ToA. For now.
The video games. So much badness (and a few decent ones, but really still off the mark).
Really, it comes down to the non-Greenwood stuff that I like the least. Don't get me wrong, there have been a few very good authors that took their stewardship seriously (and still do), and they provided some really great stuff too. But there has been too much crappy stuff to go with it.
To me, if you don't care for Greenwood's writing or ideas, fair enough. Although Ed the fiction author is very different from Ed the adventure author and Ed the supplement author. To me he shines as a supplement author. A master of flavor and fluff. Mediocre as an adventure author at best, and really hit or miss with his fiction. I actually really like his dense writing style (guilty pleasure), but the stories on the other hand aren't fantastic. On the other hand, I do know that a lot tends to get cut from the drafts, and that probably has an impact. (One of my favorite books is Piers Anthony's But What of Earth? - not because it's a good book, but the annotated version compared to the published version is amazing. Along the same lines as Terry Gilliam's movie Brazil.
I know there's a lot more, but those are things I can think of now. Did that help?
