1.) Make it so we can queue up for the ranked Pet Derby / PvP anywhere you are as an option on our PvP page so those of us that are trying to focus on that AND leveling don't have to spend 10 minutes running back to requeue after every single match then teleport back to continue with our leveling.
2.) Create a Hotkey to mount and dismount your last equipped mount.
3.) Make the hotkeys customizable. I know everyone loves wsad, but some of us use edsf that play other FPS games to give our pinky more hotkeys to use. But in general, having this to be more flexable would be great for everyone.
The last two are perhaps petty, but the first item is a real issue. Thank you for your hard work.
I like your idea about pvp on-the-go. Because, in reality you don't stop a fight and say "Let's go to ring." But, I would ask that pvp be restricted to upper levels, because it gives them something to do after questing, and prevents newbies from getting items that they shouldn't have.
Custom Hotkeys is not a good idea. It makes things to confusing. Though, I do see if your left-handed how a right-handed keyboard layout would be a problem.