|Darigaaz the Igniter|
Feats aren't free; the feats you're pumping into making your blast spells as Michael Bay-esque as possible are feats you're not spending on other abilities (like Improved Familiar, item crafting, Combat Casting, Improved Initiative and Augment Summoning). Similarly, if you take the Admixture wizard for the ability to cast Frostballs and Acidballs, you're passing up the opportunity to be a grapple-immune Teleportation specialist.
Basically, for 20% of your character creation choices, you can probably get 80% of the capacity of a full-on one-trick-pony specialist wizard. For another 20% of your choices, you can get 80% of a full summoning specialist. For another 20% of your choices, you can get 80% of a full enchantment specialist.
Why be 100% of one when you can be 240% of three?
Because you can already be 80% of many other wizard specialties without even doing a feat expendature. So you can be 100% as a blaster and still 80% at battlefield control, buffing, utility, debuffing, etc just by pumping your Int.