https://wiki.project1999.com/Cleric#Specialization
In short, there is no reason for any normal Cleric to specialize in anything except Alteration. I personally specialized my Cleric in Evocation, but that was just because I planned to solo him exclusively (and then, eventually, I planned to reset my specializations so that someday he
would have Alteration).
Also, I
think specializations only reduce mana cost, not fizzle chance? But I could be wrong on that.