What Jo'ou said, tiebreaking average speed is a mess. As messy as it is, it's probably even worse when according to Some Arbitrary Set of Stats character X is 1.01 average speed, but changing a few assumptions / different level-ups / etc. obviously can change it to below average speed, or notably faster, or whatever. (The SH3 Gilbert case, but also say FF6 Celes.) I for one am totally willing to fudge that a bit, and generally would see the PC team winning the tiebreaks short of good reason to go against. (Sadly, Rena is one of them - I'd see her as a tad slow, at least when she's casting. Fists of fury stunlock Rena is a tad fast of course.)
Definitely not behind Ashera winning tiebreak hype though, would agree with dude and have her *lose* tiebreaks. You go first and can easily walk up to her and smack her since you start close enough. (Sure, I'd give say Limstella initiative because she's got long-range and you can't get to her in one turn without getting zapped, but that's not the case for Ashera.) Not sure I agree on Snow either... his "charge times" are just the initiative bar filling up which is the same for everyone. (To the extent that FF13 turn rates differ, it's in whether the enemy is 'tied up' or not by getting hit, so theoretically Commando / Ravager are a bit fast, everything else is a bit slow. Okay and ATB-charge abilities like Lifesiphon or the Axis Blade firing off, but that shouldn't be in the speed average.) There's some mild wackiness for, say, what happens when Vanille is status spamming... it's reasonable to say that if a status is turn 1 but only hits on the 5th shot, that's happening at ~.90 speed roughly, while a status that hits the first attempt is really happening at 1.10, but that's too much of a headache.