Once a character reaches 100(1)/100, there are two seemingly perpetual things that wear on one's soul. Peak leveling and building cenedrils. It would seem that the latter could be modified to benefit the former.
The addition of peak only XP to the mirror world instances would help the endless grind toward peak 10. The character would have to complete Crossing the Mountain Path in order to gain this PXP during the mirror world run. It wouldn't necessarily have to be a huge amount, even 100 PXP per kill would be something. TP would not necessarily be included in this modification, since we are grinding our brains out anyway.
Or perhaps you could give us a monthly weekend event that offers 1500 PXP per kill for the weekend.
Let's face it, the "Summer Events and More" was helpful, but still only a small percentage of characters made it to Peak10. I have 9 characters that have reached Peak1, and only one of them made it to 10.
If not PXP, then maybe incorporate the mysterious "Stardust" that is in our currency list.
Give us something to make the Peak system more functional. Right now it's been 2 years, and the whole thing is broken.