If Dragonite got Air Slash or Wing Attack, would it be better in the flying type respect than Rayquaza?

Nonlegendary, it already holds the title of best flying type attacker, so that would make it very good against grass types, fighting types and bug types.

its like gardevoir in that respect, its the best attacker of its type, in this case flying, but its stuck with a nonflying fast move, but if that changes, it would take the spot as the best nonlegendart flying type for generations, unless staraptor gets good moves

The real problem is that Hurricane isn't that hot of a charged move. I mean, it's like Close Combat vs Dynamic Punch (Sky Attack). A flying fast move will help, but a better charged move is also a necessity. Imagine Dragonite with Air Slash and Sky Attack - now there's a fearsome non-legendary.

Dragonite is fine, it has a purpose. If you need/want to have your 4th or 5th Dragonite know hurricane you can do it. Especially with so many other dragons available.

Ho-Oh is a quite different story...it has no use for a steady player. Is there a content/back story that needs to mesh with its current fast moves? Could it one day be Aerial Ace/Brave Bird? Or Overheat/Fire Blast?