
DM_Blake |

Well, for one, I'm fairly sure they were omitted because they are not OGL so including them would be legally actionable.
Of course, Paizo could rename them and alter the wording enough to include them legally. It's not like the concept of spellcasters wanting more spells is so alien that Paizo couldn't defend itself in court (not that it would get that far) with a simple defense of "yeah, this is basic concept that any spellcaster would want so we included our own application of it into our rules".
So, to offer a second reason, they were very likely omitted just because both feats are really weak.
Gaining one extra slot that can't even be used for your highest spell level is pretty weak. Even in Pathfinder where a sorcerer has 3 extra feats (by level 20) he can still easily find 10 better feats in the list.
Even worse, learning one new spell is amazingly weak. Each time the wizard levels he learns two spells. The only time he gets a feat is right when he levels. So, he just leveled and picked the two spells he thinks are most important to instantly know. Now he's taking a precious feat to learn a thrid spell? What 3 spells are so all-fired important that the wizard is justified in blowing a precious feat to learn that third one - espcially since he can almost always just go to town and buy it from another wizard, or trade spell-for-spell for it, or steal it, or kill the wizard and take it, or if nobody else has it, he can usually just research it. And if all that fails, he can wait a level and get it for free as one of the two spells he learns next level.
No, I cannot ever imagine any mage of mine, or my players, choosing either of these feats under any circumstances.
So, maybe the real question is, why didn't Paizo include an upgraded, useful, and desirable version of these feats in their core rules?
Unfortunately, the answer is probably just one of space.
My personal 3.5 feat list has over 1300 feats on it. Most of them came from the 3.5 core books and supplements and splat books. Some came from 3rd party stuff. I plundered some of them from the internet. And I created many of them myself. I also rebalanced many of the weak feats (including Extra Slot and Extra Spell) to make them more appealing. In my perfect world, Paizo would have consulted me and put all 1300+ feats into the Core book, and it would be 800 pages long, but boy, would there be an awesome feat list!
They had to draw the line somewhere.