haveing played all 3 cc classes (before 1875 range, and after), sorc have no penalty in the mezz war if played/sc:ed correctly. 
bard has to rely on insta singel or aoe insta on the main pac healer to win if the healer spots him (wich most decent healers do).
sorc however can unstick way back and mezz at 2150 range, however since most sorcs on excal dont seem to be paying attention nor panning they get jumped + insta:ed not a very nice comination. - get jumped with any cc class and you will loose.
bard has to rely on insta singel or aoe insta on the main pac healer to win if the healer spots him (wich most decent healers do).
sorc however can unstick way back and mezz at 2150 range, however since most sorcs on excal dont seem to be paying attention nor panning they get jumped + insta:ed not a very nice comination. - get jumped with any cc class and you will loose.