Recently, as I was scrolling through the wikis and tooling around online, I had a bolt of inspiration: Wings.

They could work like this: When you summon them, they affix themselves to the back of your character. Your walk-speed would remain the same, and you would be able to perform most actions with them summoned. As with other mounts, when you take to the skies the flying mount speed buff takes over and you speed off.

I believe that these would be an excellent addition to player movement and allow for more interesting player customization. e.g. Dragon wings, fairy wings, angel wings, demon wings, phoenix wings, magitech wings, etc