I did my 3 sorc lives as a 19/1 Tiefling Scoundrel to avoid said lowbie blues. It was certainly powerful enough (because it's a sorc) but as always the caveat comes with the difficulty of content you're doing. For me I did 90% R1 and the rest maybe R3. Job done, rinse and repeat. If I were to stay at cap and want to do harder content I'd definitely want to be 20 sorc. Maybe Deep Gnome would have been better to get the extra feat from wiz level?