Story skip

[Niwashi]

I would really like to know if there will come new level "boost"/skip when next expan goes live.
Like maybe from 60 to 70 or maybe 80 and can that be used if we already have and play on a character that has done main story to 60.

A skip to get to 70, probably. To 80, almost certainly not. Skip potions are offered to allow players the option of skipping over older content to reach the latest expansion. They're not for skipping the latest current content.