@realms of chaos
No, please read what I wrote. You roll an attack roll vs a DC. That DC is equal to your reflex save bonus plus ten. Variable offense, Static defense. We do this with all saves at my table because it is more familiar with my players.

As for the difference between AC and saves there is none because in this variant, AC is replaced with a reflex save.

This is because it grates on my nerves that AC is a DC for attack rolls but uses a different progression than all other saves in the game. It also bothers me that "AC" does not improve outside of equipment.

As for armor, well I was looking for some kind of armor as DR type rule to handle that. I like seerow's version and the damage conversion variant in UA.

@just to browse
1) Yes, reflex needs a nerf. Most classes are going to end up with a medium or poor reflex progression.

2) I want iteratives. I halved the penalty because -5 is way to harsh on a roll vs. a static save.

3) Good point on the 2/5 for average, the difference is tiny and it is easy to work with fifths than twelfths.

Additional concerns:
Touch Attacks
Flatfooted condition