I had mistakenly thought the last patch had cleared up the stuttering but I just hadn't fought in a big enough battle.
1.0.6 has, at the very affordable cost of a lag spike at the start of a battle, totally cleared up the stuttering problem for me. Before there was a barely noticeable hitch every time a unit got killed - just enough to make combat feel imprecise. Now it's all buttery smooth and so very playable.
Finally the battles have surpassed warband, great work devs, didn't think such a pervasive issue would be fixed so quickly.