Achievements are very optional, bloody tokens, well, i think i have like 15k in excess of what i can reasonably use.
Honor ditto.
I am more talking about like, i dunno, mount customisations, functional (local) upgrades to your dragonriding mount, cosmetics, crafting recipes if we're really stretching it.
I mean it's not strictly speaking rewardless or unincentivised, but it could be a lot better on both counts, as well as better facilitated.
Like just spitballing here but: Some item, let's call it "war armor" that you can equip on your mount, like a "pvp mode" inside a "pvp mode" for dragonriding.
It opens up some options like, i dunno, breathing out fireballs or using a mid range dragonbreath flamethrower with your mount.
It protects against the instant dismount mechanic of the spiralling, but it also disables it for yourself. Instead you can use your own tools that are of only minor consequence for unarmored foes (think of the fire mechanic from the races), but which take a chunk of "dragon HP" or whatever off of other "war armor" enabled players, allowing much more interesting aerial sparring.
Like you have a loadout of different abilities, think one breath weapon, one armor-mounted tool (smokescreen, wind-creator, whatever), one trained technique ("do a barrel roll!", "do a salto!", etc.) sort of deal.
And then you just let the players loose in the skies.