generally, I think theres some factors that needs to be in place for a TW setting in order for CA to consider it:

a relatively well-known era for which theres some public interest, and which isnt too similar to the eras alredy used( so probbly no dark ages or renaissance)

an era in which melee combat in cohesive units were the order of the day

an era with relatively varied units, and clearly defines unit types which are relatively well documented( so no stone age or sub-saharan setting)

this doesnt leave many settings to use apart from the three, ancient europe, medieval europe and japan, which are visited.