1: We should avoid two completely different <area> elements in IS (see Christian's comment from 25 June 2021). Of the options listed there, I prefer calling the new element <genericArea>. Another alternative is something like <infrastructureArea>.

2: I find the requirement that the first and final point of a polygon must be identical to be redundant. I suggest skipping this requirement, reducing the multiplicity to 3..∞ and defining that the final edge of the polygon, from the final to the first vertex is implied. In addition to remove redundancy, this also removes the question how to interpret a provided polygon where the first and final vertices do not match. Should anyone still happen to copy the first vertex at the end, the interpretation is still unambiguous and unchanged.