In fact, the staff of assessors are smaller and the compaints to appeals boards much fewer in places that tax only land, not buildings. As for tax avoidance, there may be some owners who now are putting their sites to highest and best use and so who may get a tax break. But if they are putting their site to best use, they are depriving their community of nothing. In fact, they are making their community better. But in general, the land tax is far more progressive than a property tax.
Most land value is in urban land.
Can't get much more progressive than that.