Most assaults are too slow, though you do have a point. The Atlas 8-D does feel like a finisher to me, something that can easily kill off targets that were badly damaged by the cavalry units, freeing them up to move on to new targets. This makes me like it more actually, since it irritates me how too many people expect all 80-ton-plus units to fit themselves firmly in the role of line-of-battle smasher, denying any assault that tries to be as flexible as their lighter brethren or that fills any other role. Assault is both a weight class and a role, and a unit that fits in one category does not always have to belong in the other as well.