I think the midrange/woofer driver(s) should be powerful enough to deliver content on the same level as the LR to the furtherest seat away front the speakers/screen...CC is most likely being cutoff at 80Hz so idk about needing really large woofers unless it's a really large room and you're not running a sub.
For movies and some multi-ch music...IDK if the CC needs to be the strongest speaker of the LCR lot, but from personal experience...I would rather it be the strongest speaker, and not the weakest speaker for sure.