Granting a +2 to spell penetration is pretty overpowered IMO. Assuming someone decides to go wiz/wiz/wiz/XXX, then they would have +6 spell pen over anyone else. Combined with the FvS past life, and you can get up to +9 to spell penetration.
My suggestion is to drop the wizard past life to +1 spell penetration, keep the +2 to wand (and scroll?) DC, and add a 15% potency for wands and scrolls only.
This would have the added benefit of being a valuable past life to anyone who uses healing wands or scrolls, which is a rather hefty part of the playerbase.
I would also suggest that all past life feats should be at least marginally usefull to all classes. The melee past lives are decent enough already as it isn't hard to get a little melee capability on any caster, but you can't get much from spell DCs and spell point bonuses on a pure fighter.
In that vein, I would suggest the following:
1) cleric past life give a +1 will save bonus rather than the extra turns, and +1 to conjuration DC
2) FvS past life provides +5 jump and +1 spell pen
3) Sorc past life provides +1 evocation DC and +1 cha based skills.