Even in shorter combos, the difference in damage is really small. Ya Otome -> saika does like 2-5 less damage in most cases I've tried than EX ya otome.
Super-easy stuff like cl.C, f+A, qcf+C, (or cl.B, f+A,A, qcf+C), super cancel Ya otome -> saika might even do more than super cancel EX ya otome.