I had a feedback in my guild that the Delete option for groups is confusing and many make the error of using it instead of Delete children and group, and suggested to merge them and ask if user want to delete children or not. I'm more for just removing the Delete option.
What do you guys think ?

I've had to ingrain into users that I play with and help that you need to hit "Delete children and group" if it's an available option. Only had problems with auras getting spat out everywhere, never once used the regular delete on purpose.

I'd be fine with it.

Yeah, let's see who complains and for what reason.

Do note that we should probably do that in two steps:

1. Remove the Delete option
   and some time later
2. Rename the "Delete group and children" entry to just Delete

edit:
without a Delete option, people will have to hit the "<" on each aura & then delete the group
e.g if you put 2 auras in a group and realize that you need a dynamic group instead. mistakes will be more punishing

but it's way more annoying to delete the group w/o auras and not knowing how to multi-select auras to delete the rest aswell..... so getting rid off delete might be the way to go