F2p players leave if there are too many p2w possibilities. The game without them would be dead.
Current premium shop items are ok imho.
Purchasable lvl up - terrible idea
Just no.
I think it's the same issue around the shops. Looks like the reason is that other players are blocking your way - blocking all the spots from where you can access bank or shop. Also sometimes the game have trouble with finding path to the certain spot.