What about the rest of the banner color combinations? It stands to reason that, for balance/equity purposes, we get the rest of the +2/+1/-1 combinations, or at least a large number of them (pretty sure “the rest” is out of the question).
Possibly something like an “improved” version of each of the existing +1/+1 banners. i.e. Blighted Lands’ banner is a ‘better’ Ghulvania banner.