Yeah, going back up to speed after any action that slows Faith down is how I've mostly been using it. And while it doesn't turn you, you can use a Shift to 'drift' around a corner (whip your mouse in the direction you want to change to and side Shift the last bit of distance). Especially useful for sudden direction changes near edges since Faith can't fall when using a Shift action.
1) Have you unlocked Coil and Quickturn too? Getting all the movement skills available definitely helps. I found myself struggling to pass a lot of deliveries until I'd gone through the missions and earned enough EXP for all the movement options.
You'll want to avoid using Skill Rolls as much as possible. Only roll when there's a drop that would otherwise cause a hard landing... if you can find alternate routes that avoid long falls, even better.
The beta doesn't really explain it well, but from what I can gather you're actually referring to 2 separate mechanics here - Shift (WASD+M2, which allows you to quickly dodge in any direction) and Focus (the long gauge in the bottom left that fills up when you maintain high speed, when it's full you're unhittable). See my response to Feep above about uses for Shift.
2) The beta has a limited number of areas (only 2 out of a rumored total 10), story missions (4 out of a rumored 16-20), and skills available.
