had the times on this started yet? If not, any idea when? They announced it ages ago and said it was "imminent"

I think before it is implemented they'll need to fix the various bugs that are messing with construction.

I hope that before any new features are added, ALL the current features will be fixed, bug free...

Indeed it was planned to be introduced within the month of the announcement. However with all the problems with the server change its been delayed a bit. Expect a Sim News post when the timer has been activated.

Will we be able to see it?

When this is introduced, will there be a feature to allow the cities owner to see how much longer they have before the city collapses? I could see this coming up down the line when blank cities are put up on the market. The buyer might purchase the city to only have it fall a couple days later before they can even get out onsite to build something.

Cities currently have a made on date (like all producable entities). As for the market there was some discussion about that. Possible that only cities with more than 1 month of time left will be allowed to go up on the market. Will be dealt with by the time its released.