Syl at MMO Gypsy has a list of “turn-offs” for the MMORPG genre: features that quickly drain her enthusiasm for a game.
Here’s my shortlist of MMO annoyances:
1. Lockbox spam
This is very common in the genre now, almost every game has lockboxes dropping like rain. In most the key is only available for real-money bought currency (Zen in Neverwinter, TP in LOTRO etc). They are particularly annoying when the type changes very frequently so your bags and bank can fill with a profusion of the things. I’m just not a fan of gambling for items in my gaming.
2. Forced PVP
Nothing will turn me off a game faster than force-flagging me for PVP or giving players the power to force-flag me regardless of server type. It simply isn’t my idea of fun. The Mists-era legendary quest in WoW committed this grave sin. I include a lack of clear PVP demarcations in this category as well. Neverwinter actually did this really well – with a coloured border on the ground surrounding PVP areas and a system message warning you were close. Other games would rather just surprise you if you stray to close to the border (e.g. WoW).
3. Excessive pathing/walling
I played Guild Wars 1 despite the awful ‘pathed’ nature of the game. Zones were barely explorable at all, just a patterns of paths you could walk on and lots of intervening spaces that were effectively window-dressing. World of Warcraft even today has plenty of annoying walls blocking areas and hillsides that cannot be scaled despite how easy it looks climb. This isn’t just an “old MMO problem” since Dungeons & Dragons Online had very open areas (including jump and fly spells!) and that MMO has a very old game engine.
4. Ability shoutfest
Asian MMOs like Tera and Aion like you to hear your characters use their abilities. Strangely Turbine went down a similar route with LOTRO if you play certain classes (e.g. Warden). Such games make group gameplay somewhat annoying over time. How many times do I need to hear “YAAAARRRRGGGH!” in one dungeon?
5. Stepped levelling curve
I’m not a fan of the tendency to make the last X levels (usually 10) ‘harder to earn’. It becomes worse when the game adds an expansion and new levels but doesn’t adjust the levelling curve to account for this. Gradual progress is fine with me, I don’t need to be levelling at hyper-speed. Conversely glacial progress as an attempt at dragging out the game’s longevity won’t keep me in-game longer – I’m more likely to just move on to pastures new (EQ2!).
GamingSF 
I never thought of Nr4 but that’s a very interesting choice I can get behind – noisy characters get on my nerves quickly. It’s odd, in FFXIV most classes are quiet but for whatever reason the hunter/bard is more vocal during combat and that irked me when I played one. I would probably stop playing an MMO with overly shouty characters.
Things that come to mind for me are (in no particular order):
1: Mandatory subscription. It’s not necessarily a dealbreaker, but I really do not like paying subscriptions. I like to jump around between many different games as the mood strikes me, but if I’m paying a sub, I feel as though I’m wasting money if I’m not playing that game as much as possible.
2: Non-consensual PvP. Not a big PvP fan in general, but if I’m going to participate in it, I want it to be on my terms, and I want it to be a fair balanced competition. Both of those things are precluded by free for all PvP systems.
3: Too many load screens/excessive instancing. I’ve softened on this a lot over the years, in part because I know there are some games that just can’t avoid it (like TSW), but it still bugs me. One of the few things I still think WoW does better than almost anyone else is having a huge and largely seamless game world.
4: No dungeon finder. I can’t understand why developers don’t consider this a mandatory feature in this day and age. I have no patience left for standing around a city and spamming general chat for an hour in the hopes of maybe finding a group. If you ask me, launching with a dungeon finder in this day and age is like launching without a chat window or the ability to group with other players.
5: Gating. Just let people do the content they want to do. There’s no good reason to lock things behind arbitrary time delays or grinds.
6: Inaccessible story. This is actually what killed my interest in the Guild Wars 2 expansion. I was getting ready to give the game a second chance, but then I found it important story content was locked behind “hardcore” raids. Exclusive gear or cosmetics is fine, but there’s no good reason not to let the entire playerbase experience the whole story. TSW really does it right — dungeons and rights supplement the game’s story, but they’re not crucial to it.
7: Excessive punishment for failure. Shouldn’t the penalty for failing be, uh, failing? Isn’t having to do over whatever you were trying to do enough of its own? Do we really need harsh death penalties or other ways to punish players for having the temerity to take chances and try new things?