Adventure difficulty 15

So we have a bunch of nice adventure.
And i must say i really love the Mountain Clan adventures.
But still the maximum difficulty level is 14. And the difficulty level for adventures goes to 15.

So isn't it time for adventure which go to 15?

It would be great to have some new adventure chain which is really difficult and gets available around lvl 70.
It could be thru exelsior or maybe a new extreme long search for the explorers.

Would be great to if it would have some multi player adventure in the chain like we have with the ali adventures en de tailor adventures.
Cause it would be more harder adventures it would be interesting to play it with more people.

I remember from the times the tailor adventures hit the game we in my guild always played it together. At that time we didn't had the resources yet to play it alone. So with a new harder to play adventure i think this would be optional again.