While reading the commit, out of the berzerk/trog nerfs that were announced after several berzerker managed to win the game during the tourney, it looks like teleporting will become more difficult too in 0.9 :
Remove the Teleport Self spell
It existed as a spell, ring/evocable property, wand, and scroll. Of
these, the spell is probably the least used and the least interesting,
especially since the ring is fairly common and provides a similar
renewable and cheap source of teleportation.
Just hope you will find a ring or a wand of teleportation somewhere, as teleportation scrolls have an unfortunate habit to be destroyed by fire a few turns before you need them
And additionally they increased the difficulty of the ascension after fetching the Orb of Zot for which teleportation and teleportation control were survival items when you were running from stairs to stairs and suddenly piles of demons and pandemonium lords were spawning near you :
Make the orb interfere with teleportation and teleport control when ascending
It has a 50% chance of increasing the delay before a teleport kicks in,
and a 50% chance of adding extra fuzz to a controlled teleport.
Personnally, i wish they made the Orb escape actually fun instead of just going to make it more difficult, with the Orb preventing you completely to teleport or blink but allowing you to blast those pesky demons by increasing a lot either your combat damage or a lot spell damage depending on what class your character is during your escape.
It would feel much more rewarding like this in my opinion