All my experience was from the european servers. We had an uncountable amount of incidents where players that were put into our parties through the LFG tool would roll need on absolutely everything. In fact the final month of me playing it I don't think I ever went a single day without seeing at least one or two ninjas in a dungeon party.
Yeah. That happens. It doesn't really matter though in the long run, especially when you can also roll need on absolutely everything and then redistribute it to someone other than the jerk.

The lack of socialbility I encountered on Warcraft was simply that almost anything I said would be picked apart and insulted, no matter where I said it. I did my best to get along with the 50+ players in the guild i was in, and though many were 'ok' I would never label any of them as a friend, they simply didn't seem to care at all about other people outside of that other person being in a group with them so as to obtain loot. Basically, driven by selfish desire. Ultimately I felt no desire to talk to anyone when I was playing because I felt that my 'light-hearted' personality had no place in the everyday conversations they had. I especially could never mention anime, EVER! The second I mentioned anything even remotely anime-based, be it guild chat, local chat, trade chat or any other kind of chat, I was verbally beaten down to the point where I wished I had the power to ban all of them from the game permanently just to do the server a favour.
Why not just go join another guild? If none of them were "friend" material, you could have easily excused yourself and joined a guild that was a better fit, and there's nothing wrong with that; it happened all the time in my old guild. If you left on a positive note, the guild leadership might even vouch for you when you go to join other guilds.

Most of the best guilds on any server are filled with good people, but they also have a specific culture most of the time; if you don't fit into that, you probably shouldn't join, and they'll likely make this clear during your application by asking questions relating to language and such.

||The math freaks that play are obsessed with pulling the game mechanics apart to push their DPS, healing, and damage mitigation to their limit.||

It was these people I found the worst. Most dungeons I went into, if there was a DPS Deathknight or Paladin in the group they'd spend the whole dungeon spamming the party chat whenever they were at the top of their Recount. They were quite often the ones that rolled need on every single drop.
I was talking about theorycrafting, not meter spam. Anyone half-way decent knows better than to spam meters after every encounter.

||They still had you discover the entrances (at least for a while; don't know if they still do)||

No they don't anymore, you can now instantly queue for any dungeon of your relevant level regardless of if you've been to the entrance, or even to the zone it's located in.
Biggest problem with this was when I got alts to BC content. If ever there was a wipe on Hellfire Ramparts, which was horribly common given that Deathknights basically started at that level and they all thought they could tank without the tanking skills they didn't have yet, most players had absolutely no clue as to how to get back into the instance to recover their corpse, therefore the first wipe there was usually the last.
It's funny that they never think to follow the minimap arrow that points to the instance portal where their corpse is, isn't it?

Also, I was on a roleplay server. There was absolutely no roleplay going on anywhere, and when a couple of people did pop up and begin roleplaying at least 5 people would instantly run over to them and insult them until they either logged out or moved elsewhere.
I hate to be insulting, but you should really know better than to roleplay in an MMO. I'm not saying that because people are often dicks to RPers, but because roleplaying a believeable character in an MMO is impossible given the sheer absurdity of the game mechanics. Handwaving Van Cleef's constant deaths as "we fought an imposter" or something like that is weak reasoning that kills the believeability of the world, which is important when you're roleplaying. I found I enjoyed the game more when I stopped trying to rationalize the game mechanics and just went with the flow.

Quite often I'd get laughed at when entering a dungeon just for the gear I was wearing, I'd be insulted just because I was playing a gnome named Gnibbles, healers would call me a 'paper-tank' and leave the moment they entered just by taking one look at my health bar or equipment, even though I'd run the dungeon perfectly 2 times already that day.
"Gnibbles" is an awesome name. You should feel proud.

Y'know I thoroughly shocked one person on it once. I was making +HP rings to boost my jewelcrafting, and I saw a Paladin tank that didn't have any rings equipped, so instead of selling two of them to the vendor, I offered them to him. He was so shocked that someone had offered something to him politely, free-of-charge, at first he thought I was going to do or say something nasty if he accepted the trade offer. It took me a few minutes to explain that I really did just want to give him the rings for free just to be nice, as they'd benefit his tanking.
When I told my guild this a minute later however, all most of them could say was "Haha what a noob not wearing any rings as a tank" or "wtf ignore him and sell it". They didnt understand that I'd much rather give something away to help a fellow player than sell it to benefit myself, after all, the person I'm nice to today could be the tank I do a dungeon with tomorrow.
That was a nice thing you did. As before, if your guild was filled with assholes, why'd you stick around?

||I'm also unsure how they made the game more addicting. Could you elaborate on that?||

I can elaborate on that. To make the game more addictive they added much more PvP and PvE based content. The PvE content was made to be easier, faster and more rewarding. This caused players to be able to run through 20+ heroic dungeons a day and by the end of a week be in a full set of tier gear no problem. Ready for raiding.
Raids also were a cake-walk, it was easy to go into one and faceroll it. Because all classes were as simple as *press specific numbers on keypad in a constant loop* you could literally just stare at the battle going on and not really use any effort at all. It's been shown many times that sometimes the simpler video games were the most addictive, it didn't get much simpler than Wotlk raiding.
Ontop of that they have hundreds of collectable mounts and pets, as well as achievements, they were 'reasonably' easy to aquire but may just take time to get hold of. People (including myself) would waste days going back to old content on new maxed alts so they could get these.
So the game is addicting because there's lots of stuff to do and it's accessible by pretty much everyone?

Also, I disagree that raids were all cake. Some fights certainly were, regardless of whether it was your first time or your 100th time, but most fights offered a reasonable challenge, and hard/heroic modes required good players to clear. My guild never got past heroic Sindragosa on 25-man, and it took us months of effort for the other heroic bosses in ICC.

Also, collectibles aren't a bad thing. Even FFXIV has them, what with the seasonal gear and such.

other MMO styles such as EVE Online I could enjoy for a bit, but once I got deeper into it and experienced the ruthlessness of how I was expected to play first-hand I couldn't carry on, my personality isn't suited to that kind of merciless ferocity. (I lost an abaddon to a gang of pirate-players that I'd just bought by buying a PLEX for £13 and selling it for 300 mill to afford the ship and fittings)
The first rule of EVE is not to use anything you can't afford to lose, especially in lowsec and nullsec.

Granted FFXIV is also nothing like WoW in most of it's aspects, but I was desperate to finally get away from that horrid game so I poured my heart and soul into learning how to play this game.
Of the few things I've done in my life that I can proudly say I'm truly glad I did, joining FFXIV and finally putting WoW behind me defenitely sits in the 'top 5' list.
Top 5? Really? I hate to insult again, but you need to expand your horizons. Quitting WoW for anything should not be that high on anyone's list.

P.S. I did play on North America.