So I've been getting through Elden Ring recently, and I've gotten decently through the Haligtree & Elphael. Both are pretty fun; despite the many, many gravity related deaths in the first chunk of the Haligtree, I do appreciate the mix up it provides and how it acts as the final challenge of the platforming ER asks of you. (In the base game at least, I haven't touched the dlc really yet)
I do also appreciate getting to see the Funky Lil Guys™ that are the Oracle Envoys. I say this with joy and whimsy in my heart: they should be friends with the Amana Priestesses from Dark Souls 2.
An observation I had while playing, though: narratively and even in enemy design (not necessarily boss design), Elphael is just Irithyll but gold. We have:
Elite Knight enemies with swords and scythes (Cleanrot Knights & Pontiff Knights), two greater enemy types of that are abominations; one of which is on a bridge (Rotten Erdtree Avatar & royal revenants as opposed to Sulyvahn's beasts and the Deep Accursed), Aldrich (Ulcerated Tree Spirit), two competing religions (Kindred of Rot and the Haligtree faithful compared to the Way of White and Aldrich's Faithful / the worship of the Deep), a dead city mourning a god-like figure (Gwyndolin and Miquella), a talisman / ring that hints that even after everything a family member is still beloved (Marika's Soreseal and the Ring of the Sun's Firstborn), an NPC that you kill if you follow their questline through and can be summoned to help with their final fight (Anri and Millicent), a sibling that is left waiting forever for an impossible reunion with a brother while sitting on a chair (Yorshka and Malenia), and enemies that have way too many limbs that stay in the water (the Kindred of Rot).
The only thing I can think that is missing is an equivalent to the Anor Londo Archery Club. Also instead of going up to Anor Londo to face the feels and horrors, you go down to the Haligtree 's roots to face the feels and the horrors. True Horror™, mind.
They also have the effect of making me really heccin sad, actually. Like, on a personal level. Maybe one day I'll try to break down how and why the games create that wonderful emotion, but I don't want this to get too off track for what is a light hearted, kinda jokey comparison.
... Yorshka and Malenia should be friends, actually—