GSF evocation Acid, always add 4 to -2 ac DC

[Astegard]

A lot (if not most) acid damage spells are actually conjuration.
This results in the DC of the -2 AC effect (for having GSF evocation and acid weapon) to be very low as you are missing the +4 form GSF on it.

So in combination with having to use non Evocation spells to do acid damage (and thus easier reflex saves)  the current chance to proc the -2 AC is lower as well.
You also cant specialize wizard wise as acid evoker as you lose  conjuration (and thus most acid spells).

Suggestion:
Always add 4 on the DC to the -2 AC part. (if possible only for non Evocation spells of course else those would be +8 DC)

Main culprits are:
Acid splash cantrip
Acid arrow tier 2
Acid breath tier 3

[Astegard]

An alternative that would ease a lot of problems would be to make the cantrips that are conjuration evocation instead.

Ray or frost and Acid splash in this case.

They both dont have a DC of their own so changing their spell school wont matter.
Regardless of wizard specialization you also keep all cantrips I think.