Yeah, I agree. I don't think I ever used a set class because a great part of the satisfaction for me is in creating my own characters and seeing how they work out. In regard to battle mages, the offensive power of stealth (Invisibility used well, Sneak and perhaps a little Chameleon here and there), combined with custom offensive spells and enchantments (e.g. Soul Trap+Drain Health+Elemental Damage+Elemental Weakness+Magic Weakness) make for extremely powerful capabilities that straight-up melee or stealth+melee just can't match. Add Turn or Command to these and you have to crank the difficulty, else it's just too easy.

I last played a female Redguard kunouchi born under the Mage birth sign with combat specialty, who developed her magic and stealth skills, and thoroughly enjoyed her. It took a bit or tweaking to make her look Asian, but in the end I succeeded in making a character than I don't get tired of looking at (one of my gripes regarding Oblivion--it's hard to get a look going that I like).