Like others have mentioned, using Mending is still a better option. Additionally, you can easily get over 64 bottles of Dragon's Breath each time you fight the Ender Dragon, so this change wouldn't make repairing the elytra much more challenging.
I make suggestions...
→ Ocean Improvements (Part 1, 2, 3)
→ Improved Player-Villager Interactions
→ Balance The Hunger System