Your experience is different from mine. I find no difference in the size of the sleeve head between a regular shoulder and shirred shoulder when controlled for the same maker. I find the amount of drape has greater effect on comfort during movement than the size of the sleeve head.
+1. If anything, a roped shoulder (combined with a fuller sleeve) gives a bit more room. I have one suit with a spalla camicia shoulder in the same width as my suits with roped shoulders and it actually gives me less room around the shoulders.