The problem is that it isn't an issue for the developer. Now, if the developer continued to pay the property tax on the part of the property they are keeping (and that is what a deed restriction is, the original owner keeping part of the property, specifically, the right to higher uses) then the perpetual deed restriction is ok. I think most developers would fight hard against a law requiring them to pay the property tax on the difference between the current value and theoretical highest value. Of course, that value would start at zero or near zero, but over decades it could get very large.
I'd say that if it's an issue, the developer can include the 25-year limit in the original terms.
The problem is that it isn't an issue for the developer. Now, if the developer continued to pay the property tax on the part of the property they are keeping (and that is what a deed restriction is, the original owner keeping part of the property, specifically, the right to higher uses) then the perpetual deed restriction is ok. I think most developers would fight hard against a law requiring them to pay the property tax on the difference between the current value and theoretical highest value. Of course, that value would start at zero or near zero, but over decades it could get very large.