The Battalion is just too big to be used effectively in anything below 2500 points. To use it at anything below you'd have to run MSU (Multiple Small Squads), which is not how Free Peoples want to be run, with how our allegiance abilities and unit bonuses work.
On an unrelated note, I'm surprised I don't see more people run the Knight Azyros in their lists. A cheap, durable, fast moving hero that now not only buffs your shooting, but melee as well (re-roll 1s). There's nothing quite like your opponent's face when you roll 30 Handgunners on 2s re-rolling 1s. The once per game mortal wound bomb is just icing on the black-powder cake.