AZ hitters are more agressive and put the ball in play more often. The Tex pitchers have more pitches.
Then you go further West to SoCal. Agressive hitters, pitchers and coaches. Coupled that with year round play and you get those amazing teams year in and year out at ASA Nationals.
Texas softball is improving though. The one thing that I have come to notice as I have witnessed Select softball for just a few years is that the teams that have aggressive coaches are the most successful. That does not mean that they are teaching them proper mechanics when fielding, hitting or throwing but at least they pitch, run, hit and swing aggressively.
And yes Texas pitchers have 5 different pitches(cannot throw them for strikes for the most part) by 10U where from what I here AZ/SoCal has 2 pitches by 10U maybe 3 pitches by 14U and after that it varies. AZ/SoCal have great command of these pitches and are very successful. There is some pitchers that have high command of more than 2 pitches at an early age but that's rare. I have asked a lot of successful pitchers from different orgs here what pitches they throw 14U and under and they tell me fastball and changeup. Some have a third pitch they have high command and throw it as well. One theory is that you should not throw fastballs as a softball pitcher but I disagree. The softball fastball is not the same as a baseball fastball because of the spin. The softball pitcher creates tremendous downward spin on the fastball vs. the baseball pitcher that is actually trying to throw a riseball(does not exist in baseball). The baseball 4 seam fastball with a true 6 to 12 rotation will stay straight vs a softball fastball that has downward movement. Especially at an early age when you are trying to build mechanics into a young athlete. You throw in a drop curve, curve, riseball, screw, knuckle curve, drop at an early age and there goes the mechanics.
So if the pitchers throw less strikes the hitters take less swings. End result the pitchers and the hitters take longer to mature as a softball players.
JMHO my daughter has only played Select ball for a couple of years so that's all I have to go by so I'm sure there is other points of view out there.