An (admittedly not so minor) tweak to Elytra mechanics to try and make things a bit more balanced. Originally, I was going to implement Mojang's idea of only damaging Elytra when boosting with fireworks. This proved more complicated than expected, so instead, Elytra will now consume a (configurable) amount of EXP while the user is in flight, and will only take damage if the user's EXP is fully depleted. (At which point they'll take damage fairly rapidly.)

• By default, Elytra consumes EXP at a rate of about 2 orbs per second of flight. This can be changed using gamerules.
• When the player's EXP runs out, Elytra occasionally make hissing noises and produce bursts of soul fire particles to warn the player that their wings are taking damage.
• When Elytra is very low on durability, it makes an incessant hissing noise, and emits a trail of soul particles, giving about a 10-15 second warning before breaking.

This has some pretty big impacts for gameplay, which I may or may not have tested thoroughly. Namely:

• Elytra can still be overpowered if you happen to have an EXP farm- however, (unlike their current state), they thus still require some form of infrastructure as a mode of transportation: you either need sources of EXP at other destinations, or a big enough supply of Sculk/Experience Bottles to always ensure you have enough fuel. This is my biggest qualm with Elytra- with sufficient enchantments, they essentially allow the user creative flight, with next to no downsides.
• Enchantments such as Mending, Unbreaking, etc; are now largely pointless for Elytra, as they'll only repair already damaged wings/slow the breaking process respectively. ...However, I might be convinced to add some enchantments specifically for Elytra. It wouldn't be too hard, for example, to add some form of boost enchantment that consumes extra-large amounts of EXP for a powerful thrust; or an enchantment that could rapidly burn through EXP to increase the Elytra's speed, similar to fireworks.