I'll just answer a few of these, because why the hell not? :P
@Gynomancer1- The ability to use a custom cursor, some means of disabling particle effects, or mob transparency
There's a way to reduce spell effects at least, but I can't remember if they exposed it in the options yet or if you have to set a console variable still. Mob transparency is not something we can do.
@TeddyTauren- An interrupt mod that tracks the cd of interrupts of everyone in my party/raid
I know this is being looked into by at least one person, but no idea what the status is (or if they even plan to release it publicly).
@Frozko- Change your gear with one click mod.
Right now there are no API functions to equip gear but I'm sure we'll see it at some point.
@sharper_edge- Vet dungeon timers. Integrated to start when you go in. To track silver/gold runs
My Stopwatch add-on (Viper's Stopwatch) will do this in version 1.1.0, including a ton of other stuff (version 1.1.0 should go up later today).
@mcshane562- please god make a DBM wtb knowing when kuralak's next egg phase is
I know that someone is working on some boss stuff, but not sure about the scope of it.
@MitSenf- one that fixes the terrible body sizes for female characters.
Not something we have control over. :)
@UnimportantHero- Fully voiced quest text would be great. Hearing one set of words and reading another set is no good.
While technically possible you're asking an add-on author to record voice-overs for all quests lacking it - that would be an insane amount of work...
@TheCapodecina- As a Settler it would be nice if i could collect resources from my mount. Maybe a mount addon that does something ;)
The only thing that could possibly be possible would be to auto-dismount you. At least an add-on won't be able to circumvent any obstacles in terms of being able to do actions while mounted.
@Wanderlust_Pony- How about a mod to turn off Guild and Circle logins/outs. 100+ person guild makes for a Matrix style chat window.
Check out the Wild Notifications add-on.
@unbansogos- good nameplates
This is something I personally want to look into as well, because yes, right now the options are not ideal. But nameplates are a lot of work and I'm sure the API itself is making some things difficult as well.
@the_cajungeek- Chua punting