In my experience, a shooting star (in English) means someone or something that shines brightly for a few minutes and is then extinguished and falls to earth (the translation Eintagsfliege was suggested on pt, see below).
Certainly in German it is a wholly positive metaphor, applied to something that goes up and up rather than down and down. This despite the fact that meteors fall in the same direction in Germany as they do in Britain, and that is not up.
But maybe other English speakers have met the positive use? That is the impression I got when I last investigated the matter on Google.
Matthias in the pt group at Yahoo reported today on an interview with Hilary Hahn on the HR2 radio station. I don’t know if she was speaking German or interpreters were used – probably the former – but she’s a native speaker of English.
HH is full of praise for her collaboration with the conductor Gustavo Dudamel.
ANDREAS BOMBA: [explaining] … the shooting star from Venezuela …
HAHN: [indignant] No, I hope not! I hope he isn’t a shooting star.
BOMBA: [continues with his questions without reaction]