> One of the ideas is to allow anyone to buy a property at its set value at any time (giving a reasonable notice period, I presume). The property owner is the one who sets the value of the property.

I must be misunderstanding something, this is how any free/mixed economy works, including in Canada and US. You may make the property owner an offer at anytime, and the owner sets the price by either accepting or rejecting an offer. The problem is the buyer can't just do anything with the property (like subdivide/build apartments) due to zoning laws.