[Shujin]

Ice tiles are already pretty garbage, them not lasting long makes them even more useless as they are. They are not even good with frostbite. Expand ice is the only argument that might speak against it, but thats barely an issue either cause of how expensive it is if you use it solely for tile extension.

Cinder tiles have also been nerfed to the ground, though they are still good but its not the duration that really an issue.

Airshafts...We barely have any sources for them, and I never liked them because there was barely any reliable way to use them.

Now lightshafts/darkwater? those are pretty good.

I don't know, its one these cases of "Hey lets nerf something, and leave all actual problems alone." and make everything even more micromanagement.

Remember when Traps lasted only 2-3 rounds? Remember how no one used them cause you couldn't plan ahead and there was no reasonable way to preassure people with it before they expired? Similar went for tiles they are so ignorable 70% of the time that their lasting has never been an issue outside of cinder tile push/pull builds which have been fixed.

I mean 6 turns is probably fine, but geez it really never has been an issue for half of the tiles. IF you do that sometiles need some extra love.
Like I remember dev mentioning that standing on no allies ice tiles could lower Evade. Sure its another "nerf" for evade, but atleast ice tiles do something then, besides looking pretty, outside of expand ice.

TL;DR:
Look at what tiles are actually an issue instead of giving all tiles the same treatment.