What prevented taking water, having it analyzed, and then taking earth with a high probability? He would have reached level 14 with 2 expert schools.
Mostly, it was hope for better skills. Although at level 7, where there was a choice between initial water and advanced wisdom (the only non-expert skill), one should have thought about it and most likely chosen water. And then, abandoning that tactic, he would indeed have become a Tazar with expert earth by level 14. It turned out to be quite instructive.
While I have the opportunity, I'll ask one question about leveling up. I've heard of a rule that every 6 levels, wisdom will be offered at least once, and every 4 levels, magic will be offered at least once. Where did these rules come from, and is there anything similar regarding other skills?