Indeed, the problem there was that was before matched play and they were building a narrative more than balanced armies.
It's likely any Aelf battletome will either combine them or give bonuses for using them together. I'm hoping the Azyrheim Lancehost becomes it's own thing or takes in the Order Draconis, it's also interesting to know that their first campaign was in the realm of fire where we first hear about human kingdoms surviving while under chaos' rule but still resisting. One of which is kingdom of Volpone which lost a large army of knights and has a sacred river. So a army of human and aelf knights aided a land filled with more knights, something good can come of that.
The Swifthawk Agents are probably the safest bet, besides their starter, as the grand alliance book gives them more detail than the other subs, they are rebuilding their lost sky fortresses, they have the sky-cutter which was a AoS pre-planned model in 8th and there's a recent focus on sky armies in the lore with Destruction having the most with three groups and Order only having the Overlords and Aelves. So they're likely to get something.
With the general handbook 2 coming out we'll see more battletomes as well so here's hoping one of them's for the aelves.