The current system with Echo clearly does not work if we are getting nerfs.
The 51-59 dungeons, Ravana and Bismarck HM, do not have echo. So yeah, it's not "not working even with echo". In fact I know of no story mode dungeons that have echo.

Stuff that has echo: old Coils, (pre-HW) HM primals on death after 3 minutes, (pre-HW) EX primals on death after 3 minutes, solo story instance after 2 deaths, class quest instances after 2 deaths.