A helicopter sounds great, but perhaps it would make sense to try to simply make a probe that can stay alive there long enough to do anything other than send a couple pictures back.
Venus, definitely. Titan though? Huygens is the only probe that's ever touched down there, and it's operational life was tied to its battery life and the fact that Cassini wouldn't be around very long to listen to it. Cassini was on a flyby trajectory, not an orbit around Titan, so as soon as the orbiter went over the horizon, that was it. Outfitting Huygens with enough power to stay on for future flybys would require MUCH more power, a job for which only an RTG would be appropriate since solar is out of the question that far out/under that atmosphere, and batteries just flat out don't last that long.
Nothing about the moon itself prevented a long operational life.