I'm having a hard time understanding some of the points you are trying to make. For example you have this:
but then So you are saying this should be a stepping stone, but then turn around and say that stepping stone won't motivate the majority of the player base to engage with them.
On top of that, you say but then later say
So adding more steps wouldn't make it even more confusing? Naming is naming. WoW has LFR, normal, heroic, etc.
As for difficulty, this is always going to be subjective. How many different versions are needed when for some, EX is too difficult, but others say it's midcore. People complain about lack of content in patches now, can you imagine how much less would be in if they say "Here is the new trial and it's 7 different versions?" because everyone has a different definition of what is difficult?
I'm not saying the idea of what you are saying is bad. However, at some point, no matter what you do, people are going to be cut off no matter what.