-This review is spoiler-free other than a few boss names and vague complaints-

I started the expansion at level 107 with 30 vigor, using Morgotts cursed blood blade until quickly switching to the Milady for the rest of the playthrough. Explored absolutely everything I could, and fought Messmer at scadu tier 10, and was I think scadu 17-18 by the final boss.

The major bosses were all very very well created and just the right amount of challenging movesets and learning how to fight them is considerably more fun than 90% of the base game bosses.
My only move complaint is when Gaius charges at you, its a 50% chance of getting hit when dodging horizontally because he reacts and turns too quickly and has too long of a lingering hitbox, and the only way to make it consistent is to make yourself light load or use an ash like bloodhound step, but it really is just that one attack that is the issue with the fight.
Messmer is a perfect step up from Malenia in a way that felt similar but less obnoxious, had hard moves but very learnable and very fair. At no point did i feel frustrated when fighting him, it all just came down to my execution of it.
DBDL (Ill use acronyms for spoilers sake) is a brilliant design, the music was amazing, and the movesets were once again learnable and dodgeable but with the right amount of challenge. Also creepy af.
BTD is by far the coolest and well designed fight i've ever seen and played in a souls game, especially for *that* genre of creature, which notoriously is not done very well in FromSoft games.
"Cave Yoda" caught me off guard and is hilarious, thank you Miyazaki.
RTMK reminded me a lot of Nameless Puppet from Lies of P with their moveset, and honestly I think this boss should've had a cutscene. At first they seemed impossible and constantly countering my every move, but within 7 attempts I started seeing the patterns and learned it, which some newer fans of the game seem to not be able to understand, and expect everything to be readable immediately, and thus claim "game too hard". Patience and Pattern recognition is required for souls games and a lot of people don't seem to have that. You should always first assume you are the problem or are missing something important before blaming the game, especially in a game like this. I understand fights can seem unbalanced but if you go watch any good player do the fight, you will realize you are most likely the issue.

They implemented a system called "Scadu Fragments" which has been very controversial among players. I immediately saw the fragments as a way for people to be able to play the DLC at any level as long as they've beaten Mohg, as it "balances" your damage and defenses for the DLC fights, while being disabled outside of the shadow realm. Others saw it as a required "explore everything or else you can't fight the bosses" or "free cheat items" which is somewhat understandable but is not very smart considering the whole consensus around souls games, ESPECIALLY Elden Ring, has been "if you can't even get close to beating a fight, go explore other areas and come back later, most fights are not required for progression". People seem to get mad when their level 300 character gets one-shot right when they jump into the expansion, but if you bought the expansion just to steamroll all the bosses... that would be a waste of a DLC and $40. So I think the scadu fragments are a smart way to balance out everything since there's no real way to know what level you are "supposed to be" at any point in Elden Ring.

Performance issues seem to be a huge issue for a lot of people, which makes sense to negative review for, especially if that same pc was able to play the game perfectly before the expansion. However I did not have any performance issues and only a few lag spikes after having the game open for 5+ hours.

I felt the world was much larger than I expected, which is nice, but some places felt really really empty, like the Finger Ruins, Hinterlands, and Abyssal Woods. I expected so much more and some places all we got were some smithing stones, a talisman, and a boss fight that we already had 3 times in the base game. I understand time crunch and money issues, but I really think Fromsoft should have spent a lot more time on having more unique enemies/bosses because going into the DLC and seeing 3 dragons that are identical to base game dragons except the element is ghostflame, 3 more dragons that are just Agheel but with some of the most pathetic lightning attacks I've ever seen, another fallingstar beast, 2 ulcerated tree spirits, 2 death rite birds, a tibia mariner, another ancient lightning dragon, 2 tree sentinels, a leonine misbegotten, and a magma wyrm, is incredibly disappointing to say the least. There's also SO MANY NPC FIGHTS at the end of long dungeons or caves which is so infuriating since the NPC AI is garbage and so many things just cheese right through them. That being said, all the NEW bosses are decent at minimum and amazing at best.

In regards to disappointing areas, Abyssal Woods deserved to be scarier especially with that haunting message setup in the beginning which actually gave me chills. I was hoping for a giant shadow creature of sorts to be wandering around but instead we got an average Assassin's Creed stealth mechanic, hiding in bushes from a few creatures that were not scary in the slightest, that just walked back and forth in a small line.

Questlines are as vague and convoluted as always, and I don't know if this was the case before, but requiring you to summon a quest NPC for a very important boss fight (including the literal final boss), thus increasing their health pool and getting a useless teammate that dies in a few seconds, to proceed a questline is ridiculous. I did not use summon ashes the whole game and I did not want to start by summoning Thiollier the Useless at the finale.
(Update: supposedly the boss health bar does NOT increase as long as the summon symbol is inside the arena, not outside)

FromSoft please fix the NPC AI, they don't know what to do against the Wing Stance heavy attack and u can literally just hold LT and click RT for every single NPC fight (except lamenter)