After seeing the first animations video and Gosetsu in action, we've effectively only seen the basic 1-2-3 combo and the cast time Iai skill. I wouldn't say Iai Shoten is a combo ender, but it may be something like a skill you build "stacks" for, then gain access to that or other skills that would be a damaging skill, but with a cast time. This is only speculation, of course.
