Somebody needs to go back and test protectra/shellra/bravera/faithra and come back and redo their whole list.
Seriously though, I don't wanna like... "tear down" your post but damn... craziness.
First off, Light:
Yes, she's fragile. Not so much so with protectra/shellra. Her chain building is utterly unmatched. Her damage per swing is not so impressive, but the rate at which she attacks makes up for it easily. Her enspells fill in for her otherwise shitty syn beautifully, she casts haste and enspells while fang and van get everyone protectra/shellra/bravera/faithra'd.
Fang:
Untouchable damage. Great defensively. *BEST SYN IN THE GAME*. Seriously, you're WAY underestimating the -ra buffs, which she gets *all* of, PLUS haste. Great sab, albeit can be a pita to land her debuffs.
Snow:
is a fantastic SEN, and a pathetic everything else. His ATB gain is too low to be any good as a RAV, and his damage is inferior to light, fang, and situationally even Van, as com.
Hope:
Hope is just terrible, period. The only thing he has going for him is haste as a healer, which is meaningless when you get near endgame and everyone has haste. His damage is a joke. His chain building is nothing special. His healing pales in comparison to Van. His buffs are a joke compared to anyone with -ra. Seriously, hope is easily the *worst* overall character. At least Sazh has points of usefulness. Hope is *never* better than Vanille. Period. You're always better to have her as long as you have someone with haste, which is always by the time he has it.