Finished Shadow of the Erdtree after having dropped it on release and then again like two months after that. Got to explore more and with the help with a few guides got to find locations I thought would only unlock after beating Messmer. I wanted to keep my guide usage to a minimum since I didn't want to spoil the experience but after the whole "NPC quests advance if you get too close to the shadow keep" (which also made me drop the DLC the second time) I decided using one was for the best, specially since I intended to play the DLC once.
After finding more scadu fragments I finally began having fun against the bosses since they no longer felt brick walls that hit like a truck... until I reached the final boss, that piece of shit nearly made me drop the DLC a third time yet I prevailed (the NPC summons, as nice as they may be lorewise are such a detriment holy crap). Beating the final boss was such a rush, felt great and then the ending left me feeling both confused and empty like "is that it?".
Overall I have mixed feelings about the DLC, some areas like abyssal woods are fantastic but at the same time they felt undercooked, take Midra's dungeon for example: It is stupidly tiny and the rest of abyssal woods doesn't have much to it.
When it comes to exploration it's way too easy to miss stuff since the DLC is, in my opinion, too vertical. Sure you might see a village at the bottom of a cliff but since there's no obvious way to go down one may be assume that you gotta advance the story someway to open the way foward, when in reality the entrance to such village is hidden in a place that makes little sense and there's no intuitive way to find it.
The shadow realm blessing is both genius and annoying at the same time: Genius because it forces you to explore and not rush for the main bosses, annoying because it may kill any interest in a repeated playthrough, even more so if you add in the requisite of killing Mohg to enter the DLC to begin with, and it sucks since the DLC has plenty of choices with vastly different rewards which leads to my next point.
The NPC questlines SUCK and I totally get people who complain about them: Just getting close to the shadow keep breaks Miquella's rune which causes you to miss on dialog and potentially rewards. People might say all fromsoft games are like this but it's baffling after how well the base game avoided this bullshit. I got super pissed after finding out that merely stepping on Messmer's arena (which has ZERO indication of being his boss room) makes you lose one of Leda's/Hornsent's rewards, why the fuck couldn't they avoid moving the Hornsent UNTIL AFTER YOU RESOLVED THE WHOLE INVASION THING? The DLC is full of shit like this and I hate it for it since you gotta have a guide and a checklist at all times to avoid it. Then there are the questlines themselves, you see some of the characters so few times before the fight at the end and it's like why even add them to begin with? Maybe I got this impression since I did the early areas of the DLC nearly a year ago but still.
And back to the final boss, what an awful fucking fight, the first phase is fine even if Radahn's combos are too long for my taste but then the second phase is full of BS: Huge ass AOE which I didn't even find out you could run out of until I watched someone else, the whole rush with afterimages I still don't fully understand how to avoid oh and the fact that the boss can teleport from one player/npc to another without warning is pure CANCER. I get it's the final boss of a DLC you're meant to do after finishing with the base game but they overdid it, the boss hits like a truck (discourages you from trading) and is relentless with his attacks, which is by far my biggest issue with the fight: The window to attack is so small before you have to go back to dodging/running, which is made worse by the boss having a ton of HP and no weaknesses. It embodies EVERYTHING wrong with Elden Ring's boss design.
Lastly: I was baffled to find out how many people simply gave up at Radahn, these were people who played the dark souls trilogy, bloodborne, sekiro and even done challenge runs. They just gave up and didn't even bother with it even after the boss was nerfed.