All* rooms that are either no-channel, no-fire or no-air (e.g. no ice) have been marked by a remnant of the Age of Legends, like this:
A Woodland Path
Just away from the city a path strikes off east into the forest. Trees and
bushes line the edges of the path which has been kept from being overgrown
solely by the heavy traffic the area sees. Soft chattering can be heard
from above as the squirrels note someone's passage.
[ obvious exits: N S ]
A remnant of the Age of Legends juts from the soil.
An Ogier stonemason strides by briskly.
*This doesn't include smobs. Also, I've left in the Seanchan raven statues. Lastly, two zones had so many of these rooms, they need a closer look to see if these rooms should all stay no-channel/etc. or not, and if so, which ones to keep.
In a rare few occasions, there is a group of various no-channel rooms clustered together, in which case I only marked the central-most room. Swamp comes to mind.