It's so weird to me that with our income tax laws we to try and make sure they are fair and taxing people according to their means. You make more income, you pay more taxes, you make less income, you pay less taxes. But then we layer on property/land taxes that absolutely do not follow that principle. Retired Grandma living off social security has land that she bought 50 years ago is now worth 50 times what it was? Too bad Grandma, gotta pay up or sell it and move!
While I share your reservations, I do prefer this to imminent domain (a practice I am not a fan of). I think it's more likely for the seller to get the best value for their property, and incentivizes the seller to make good use of the property.
There are already laws that are written referencing primary residence. It’s not hard to imagine exempting that and just making sure grandma only pays for her 8 vacation homes.
Why does she need to pay more taxes because she owns vacation homes? If they are generating income for her then income tax would make sure she's paying her fair share. Certainly whatever income she used to buy those homes was also taxed.