Mishna B'rura 264:1 says:
The reason for the invalidity of [certain] wicks and oils [for the Shabas lights] is that they do not shine well and we're afraid he may tilt the lamp so the oil within it will flow toward the wick so it will light well, and he'd be liable for [the m'lacha of] burning.
Lighting an incandescent bulb is generally accepted as being forbidden mid'oraysa AFAIK. A bulb not seated properly in its socket will sometimes flicker. It seems reasonable to me that one should not be allowed to leave such a light (i.e. an incandescent bulb flickering due to not being seated well) on on Shabas, and, if he did leave it on, that he should not be allowed to use it under certain circumstances, just as with certain oil lamps. Do any pos'kim discuss this case? What do they say?