5.0.4 has been announced and given an official date which means that beta testing is definitely in its final stages (not like that's a surprise or anything). For the development side of things, we're unlikely to see much more than number balancing and bug fixes rather than large sweeping changes to mechanics. That said, no project like World of Warcraft is ever truly finished and, while Mists of Pandaria is as close to "done" as we can realistically expect, there are still some changes I'd like to see before September 25th.
Disclaimer: I'm not a game developer and have an extremely limited knowledge of what actually goes into a complex system like WoW. In short, I know enough to know that I know nothing and that what I'm asking for in this post could be anywhere from a ten minute fix to a 3 month project that requires an entire team.
Search Function for the Mount Pane - Once 5.0.4 hits live servers and mounts are shared across all characters (with some exceptions), I will be sitting on around 150 mounts. A quick scan of Wowhead shows another 68 mounts in the Mists of Pandaria files. Combine that with the 20 or so mounts already available in game that I don't have (as well as a few that are no longer obtainable) and the idea of someone having over 225 mounts in their collection becomes . . . not impossible. Now, that's not to say that everyone will have that many, but I think even the 50 mount mark will be pretty easy to hit with minimal effort (42 just from currently existing Horde/Alliance factions). This means that finding "that one mount" in your Mount & Pet pane will be more than a little difficult. The pet tab has a handy little search feature to find "that one pet", can't we have something similar for mounts?
On that note, I'd also like a way to see which mounts that you don't have (again) similar to the pet tab. Currently, you need addons for this sort of thing and I don't see why that should be necessary.
Shivarra 1H Functionality for the Glyph of Felguard – I love the Glyph of Felguard. Anyone who's read some of my other posts knows this pretty intimately. I love visual customization so the changes to minor glyphs, along with Transmogrification as a whole, make me giggle like a school girl. It is by FAR my favorite part of the expansion. That said, it makes me a little sad that I'll only get to use it in my Demo spec (if I have one - as a progression raider I don't always have that luxury). This fits squarely in the "this may be a far bigger project than I'm assuming" category, but what I would like to see is the Glyph of Felguard's functionality extend to the Shivarra, allowing us to change the one handed weapons that she carries. Not only would this add more flavor and fun to the glyph, but it would also make it a viable option for Affliction and Destro locks, if only those specced into Supremacy. The Talon of Azshara model is cool and all, but I can think of a few others I'd also like to see.
Easier Dual Wielding for the Wrathguard - On the same note, I love that you can use the Glyph of Felguard to change both of the weapons your Wrathguard uses. However, every time I've seen someone talk about how awesome it is to dual wield (typically in a video game setting, of course) the discussion usually revolves around dual wielding two of the same weapon. Currently, the only way to get your Wrathguard to sport two copies of the same weapon is to have two copies of the same weapon in your backpack. This seems an unnecessary and needlessly tedious mechanic for something that is intended to be nothing more than simple fun. Transmogrification doesn't require you to have two copies of a weapon to alter both of your equipped ones, why should the glyph? Especially since the coolest ones are incredibly rare or hard to get. What I'd like is for it to default to dual wielding the same weapon if there is only one in your backpack, but keep the random choice when there are several.
Larger Weapons for the Wrathguard – Perhaps this is a persistent bug, but the Wrathguard weapon size/scaling has always seemed . . . underwhelming. While the standard Felguard gets to keep his massive and intimidating weapon, the same item in the Wrathguard's hands shrinks to a fraction of it's original size. Even the really large weapons like polearms are smaller in his hands than in my characters, and some of the smaller swords or axes look more like daggers when he's holding them. I realize that there may be some clipping issues involved in his attack animations, but can we get even a slight boost? Maybe 30%? It just bugs me that the upgraded version of my biggest and baddest demon carries around weapons that are as small as or smaller than what I use. As an analogy, the change should be like going from Arms to Titan's Grip, not from Arms to Subtlety.
Unfortunately, the Supremacy demons are bugged and cannot be summoned right now, otherwise I would have some screenshots to demonstrate.
Points Dump – Not to be a snarky douchecanoe, but haven't we learned this lesson already? We had a way to dump Emblems/Honor into gems in Wrath, BoE's to buy with VP and trade goods to buy with JP/Honor in Cataclysm. However, like in the beginning of Cataclysm (which involved an emergency patch-in of a trade goods vendor because people needed a way to dump excess points), we are now without a way to dump excess points. Once we have everything we need from JP, Honor or VP and the tier continues on, we'll quickly find ourselves capped on points with nothing to spend them on. Maybe I'm missing something (I fully acknowledge that possibility), but I see no BoE's from Valor, no trade goods or gems from JP or Honor. Transmog gear from previous expansions will only take you so far. We need something else to spend points on.
Again, I may just be missing something. I hope that I am.
A Couple More Minors for Priests – This definitely falls in the "too late" section. Some specs have been pretty spoiled so far with regards to Minor Glyph options, but not all of them. Healing Priests in particular are a bit short. So far we have four glyphs that are not specific to a particular spec. One that is specific to Discipline, one for Holy and four for Shadow.
Confession - Kinda cool, I guess. Had potential to be much more interesting (at least in terms of the confessions you could get out of it), but mostly a novelty item that I feel will lose its flavor quickly.
Shackle Undead - Which we use . . . how often?
Heavens - Kinda cool, but a pretty minor visual change that most people probably wont even notice.
Holy Resurrection - Unfortunately, I haven't had a chance to really see this one yet, but it sounds cool.
[Holy] The Val'kyr - Pretty cool.
[Disc] Borrowed Time - Not bad, reminds me of something someone would put into a PowerAuras set up.
So, all said and done, after you've gotten bored with Confessions and realized that you haven't had Shackle Undead on your bars since ICC, A Holy or Disc Priest will be left with Holy Res, Heavens and Val'kyr/Borrowed Time. That's not much to choose from.
Side note: Warlocks are also pretty unbalanced with two options specific to Affliction, one for Destro and five just for Demonology. However, they have quite a few that aren't specific to a spec so it's not as much of an issue.
Wider Trade Skill Window - It’s just time to do this. It's already been done to the quest log and the result was beautiful, but the trade skill pane is still smashed into a cramped little window. Let's go to a double-wide format like the quest log and make everyone happier. To see what I mean, check out the addon someone created to do just this:
http://www.curse.com/addons/wow/double-wide-trade-skills
Seriously, once you start using that addon you'll never go back. There's no reason why this couldn't be a default aspect of the standard UI.