Possible solution to max lvl mytho/philo grinding.
Yoshi-p has said that in the patch were getting the random duty finder and the 1st time you use it a day you get bonus rewards.
My suggestion/idea for this is once you are max lvl the RDF will put you in any dungeon that you have unlocked. It will reward you 20 philo per boss kill and the final boss will reward 40 philo and 50 mytho.
This will eliminate the need to CM/AK spam to get your tomestones. It will make the grind to get raid ready less grindy as you'll have a huge pool of instances to randomly do, and it will reduce the queue time as there will be a much bigger pool of players queueing for a larger number of instances.
I see this as a potential bandage fix until they are able to give us a max lvl hardmode of every dungeon.