As I said earlier in the discussion, I would like to be a mentor for the sake of mentoring "really new" people who are only just becoming familiar with the game - because not that long ago I was the one asking those questions and I'm grateful that I got answers. Now I'm far enough into the game that I can start passing that knowledge on to others. I can guide someone through the mechanisms of Haukke Manor or Qarn or the Darkhold, or give general help with the game, but I can't help people with high-level trials.
With such a range of required skill/knowledge level in the gameplay, including optional content that isn't a prerequisite for mentorship, mentors aren't all going to be at the same ability level. Thus, it would be great if there was some way for mentors to indicate what content they are actually confident at mentoring in - ideally with the rewards for the roulette adjusted accordingly.
Did I say I was going to use mentor roulette to get into the EX trials? If you think I did, I phrased it wrong. In fact I know I can't do it, therefore it would put me in the position that despite being a mentor (when I get there), I would feel unable to use the mentor roulette because it would potentially assign me to 'helping' in a trial I don't actually know how to complete, and it wouldn't be fair on the others.
The main reason I would want to beat the EX trials and Binding Coil is so I can see the story locked behind completing it. If I can't personally beat it synched (whether through difficulty in queuing into it or lack of high-level skill / party co-ordination once I'm in there) then I will need to do it unsynched at some stage just to find out what happens.
Personal terminology perhaps, but I would not consider clearing the trial unsynched to be "beating it" - I didn't succeed in the battle as it was intended to be played, I just got a free pass through it to continue the story.