You flag it as being in the wrong forum (flag button at the top right of eac post),. I flagged it for you.
I would probably change it to be like this:
SPELL MASTERY
You have mastered a small handful of spells, and can prepare these spells without referencing your spellbooks at all.
Prerequisite: 1st-level wizard (or Magus or whatever)
Benefit: When you take this feat, you choose 1 spell per spell-level that you can cast (that you know). You can now prepare these spells without referring to your spellbook. Every time a new spell-level becomes available you can choose a spell of that level to add to your list of spells that you can prepare without referring to your spellbook.
At 5th level and every 5 levels thereafter you can choose to swap one chosen spell for another of the same spell-level.
This feat can only be taken once.
Normal: Without this feat, you must use a spellbook to prepare all your spells, except read magic.
In case I didn't make it clear enough, this would basically mean that you have one spell per spell-level that you can prepare without a spellbook. When you level up you get a new one. The ability to swap spells out ever 5 levels means that you can take spells like Daze at lower levels without ending up with a useless spell later on. Since this becomes a scaling feat I thought it appropriate to limit it to only being taken once to avoid cheese.
If you wanted to change the swap spells part to every 4 or every 6 levels or whatever you feel is balanced feel free (obviously), this was just a first draft, so I just picked a number that sounded right.
If you wanted to change it so that it can be taken more than once feel free (again, obviously). I feel like limiting it is a good idea, but you could limit it to 2 or 3 times. You could alternatively keep it at "only taken once", but add an Improved and Greater version.
Spell Mastery in most campaigns is a wasted Feat...however if you are running a campaign setting in which you are removed from civilization you may find you have more need to avoid situations like loosing your spell book and getting screwed over. I have seen this feat mostly taken reactively by players who don't trust their DM's to not screw them over, or taken when the DM has warned them in advance this would be a theme in the campaign. More frequently players would just opt for Sorcerers in such campaigns if they knew it was going to be set up like that. Properly built a Sorcerer looks a lot like a wizard and doesn't have the spell book handicap.
One of the thing not to forget when looking at the wizard vs the sorcerer is the simple fact that a wizard can change their spell selection on a more or less as needed basis, where as the player of the sorcerer needs to be damn nearly psychic themselves when choosing their spells. Sorcerers need a lot of flexibility built into their spell list (or magic scrolls, wands, etc that make up for a lack of flexibility) and thus tend not to specialize as often, nor as deeply as their Wizard counterparts. NOTE: I personally never followed this advise and always pointed out that my Sorcerer (or Mage) was there to "blow sh** up!" and the party for the most part just accommodated for this type of build.