Well, rolling Necromancy early up really sucks and I don't think a GM should force this style onto a lowlevel character. You may get the basic prereqs by level 4, but you don't get an Advanced spell until level TEN, and that's just a huge waste and won't do the character any good. The char will likely run out of Spell choices pretty soon and have to take Skill points he doesn't need because he doesn't qualify for any Advanced Spell. IMHO you shouldn't force that on a player.
So random rolls or not, the GM should have the final say if the player has to accept a random style, and shift to something more favourable in cases like the above.