Practiced Spellcaster combined with scrolls make the number of sorcerer ranks much less important, it seems to me. Even the dragons that cast as level 12 sorcerers are still trying to make a DC 18 caster level check with a caster level of 16 to cast level 9 spells from scrolls...not a sure thing, but close.

While higher casting level is obviously a good thing, what do you really need out of casting as sorc15 instead of sorc12?

Skill Knowledge is nice if you can get it, but the page it's on only suggests it in the context of alternative skill systems. Dragging that into non-variant play seems a bit sketchy.