So we could have in the massive open world land of hyrule, the equivalents of a plane, water vehicles and car.

Nintendo has no excuses.

Also the following online minigames with leaderboards using wiimotes:

- Hyrule castle swordplay

- Goron boxing

- Kayak racing (rowing)

- FISHING of course

Make your demands. 

so it should be GTA: Hyrule Castle Stories

Giving Epona the ability to transform into a seahorse or a pegasus would be cool.

If you can fly then what's the point of all other means of transportation?

...Fun?

That is true, I quite liked the bird in SWS although they could make it that each can acess areas the others can't or an RPG type approach where you get them at certain points in a certain order like the bird could come much later on.

Because logic. and GTA.

Also, having many other means of transportation would make the game much more cooler than just one. As pointed above, giving epona the hability to turn into a pegasus and into a Lapras would be so awesome. You have 1 ride for everything.

And take a look at this:

Great Idea!

Need more gray blood to be moar hardcore

The ability to fly should be a late game upgrade, or be restricted to a certain region.