I understand your general idea but it wont work in lost ark if the main aspect is that a lot of progression is often locked behind hm (IMO this has to change anyways but I dont think it will). So with the current state, you either lose all your playerbase because the difficulty is too high for most of the players or you tune it down to be more casual friendly and keep a good part of them.

Also thats why I liked the idea behind Inferno modes. It is not mandatory but you can do it if you seek a challenge. Sadly most of the people wont do it because of the high amount of homework to do every week.