i guess you didn't get the memo where spell casters are ranged and thus should stay away from getting hit because they are squishy.
None of the ranged DPS have stun/disables, except cardmaster (******* got what he deserved). Most casters have at least a disable and fiddlesticks is the prime example why all casters shouldn't have life steal. Hey why don't you stand there while I get my life back.
If you want lifesteal on a mage, play fiddle, morgana, or cho'gath with AP. Lol, or you could play Scion... because he's tagged as a mage. If you want a high spike damage spell caster with life steal you should look elsewhere.