Player Drop Off and Accessibility/Diffculty

[Shistar]

[...] ill be generous and say that the new deep dungeon is casual but its actually debateable due to requirement for entry [...]

You just have to finish the "tutorial floors" so to speak and beat one boss with a grand total of two mechanics which boil down to run away, come close, run away. You can literally get it done in one evening and do it fully blind. It truly doesn't get any easier than this...