The thing is: people want to play but most will not like all your sub-systems. Many will just play one or two of the different game modes, and now you have to create new contents for players IN ALL THE DIFFERENT PARTS OF THE GAME!
If people want more PVE combat, I think the solution will probably comes from automatic creation of new content. With the advance of AI, we'll come there eventually, but don't hold your breath.
that's why you need lots of sub-systems...so everyone can find a few they enjoy. The effort to implement a sub-system is a one-time cost, as opposed to the on-going cost of content creation. Also, a lot of players in full MMORPGs (as opposed to looter/shooters with gear grind..) dislike random dungeons, raids, etc. Seems like developers can't win!
If people want more PVE combat, I think the solution will probably comes from automatic creation of new content. With the advance of AI, we'll come there eventually, but don't hold your breath.