The optimal beginning sorcerer should have a high Intelligence to get more spell points. Endurance and Speed should be as high as possible so they can survive more than a hit or two. Personality is useless for them. The other three abilities are nice for them to have. After passing Thomas Grey's test, they get promoted to the rank of wizard.
Wizards get to use master elemental spells.
Later they can become lichs or archmages. With the second promotion, they gain access to grandmaster elemental spells, as well as to either the Dark or Light schools, depending on the path you decide to take. Dark magic is more in character for wizards, if you ask for my opinion.