On topic of improving m+ I saw this thread the other day.
Tldr:
Give keys 2-3 charges so player can have some attempts / mitigate against single mistakes bricking keys.
Have keys work in 2 dungeons at a time to increase variety and options.
Have nascent / enchanted crests be usable to increase items upgrade tracks. This is a heavy currency investment that would require killing that boss on that difficulty or earning X score in the case of m+ as well.
Rework champions peril
Revert the cc change