6 month rolling makes way more sense principally. Unless the 1-year hardliners would rather a 1-year rolling then they are simply using a band-aid on a gaping wound. A side note on the last paragraph, other than reverting segwit, taproot, and OP_RETURN, there is not a way to stop directly compilable spam on Bitcoin. All you can do is set a block limit and let the market decide. (Without having data discounts like segwit)