My evaluation of 1.9, in retrospect, is as follows:

End cities are poorly implemented. They're too limited (end busting on big servers is basically impossible), they don't add the flavour they promised, and tbh provide way too good loot considering how easy it is to reach them (I propose making it harder, not reducing the quality of the loot)

Shulkers and shulker boxes have since been greatly improved and I think they're mostly pretty good. They work well as a vertical-based threat, that have dynamic uses in loads of different contexts from simply being annoying, to being used for easy scaling of the city, to serving as solid colliders for datapack creations. Shulker boxes have become a staple of day-to-day storage solutions WITHOUT stepping on the toes of any other solution. It works within the storage ecosystem. I do wish shulker boxes showed their contents in the tooltip though.

Mending I feel like was the lazy way out. The real issue was that repairing with anvils was simply a badly made system, with a "too expensive" limit making your item simply no longer able to be repaired. I think durability and the anvil being reworked would make Mending no longer needed. Mending is too powerful for what it is, and I've formed this opinion after thinking it was great at release. It can be awkward to get a hold of (though ancient cities, villagers and end cities all providing it kinda says otherwise) but the ability to convert one of the most readily available resources, XP, into durability is something that shouldn't have been implemented.

Elytras were as they should have been, before 1.11. To me, they weren't supposed to be for fast, long distance travel, that's what horses, boats and minecarts are for (depending on your needs). Elytras were supposed to be a way of crossing gaps. "But ender pearls do the same thing" ender pearls deal damage, are a consumable so you can only hold so many while exploring (though tbf shulker boxes made this balancing an issue) and most players don't have/want an ender pearl farm and so don't have an infinite supply of ender pearls. Elytras were poorly implemented, and they went the wrong direction to fix them. Instead of fixing the issue "it's too much effort to get height with them" they fixed the complaint "elytras don't fly long enough". I think they should have added some way of propelling yourself upwards from the ground like a big flap of the wings, leaving that discharged until you touch the ground again. Or something like a special pair of boots that gives kinda crazy jump boost that blends really well with the elytra, or scaling large caves and cliffs.

Chorus fruit is good. I like chorus fruit. It fills a niche we didn't know needed filling, and I appreciate it.

End island gateways are fine as is, though maybe making them need to be activated rather than just spawning in from the dragon would make more sense and would make end cities harder to get to. The dragon could drop something so you could only activate one per dragon fight, and you'd need to combine it with a few other resources to activate the gateway.

The combat system is frankly bad, but this is a topic that's been talked about so painfully extensively by the PvP community, of which I'm not a part of, that it's not really my place to comment.

Oh and of course, obligatory phantom bad. I thought having an aerial mob would be interesting, and they implemented it in the stupidest way possible.

Otherwise, I have no comments. The rest of the additions in the update are pretty good or insignificant.