For dead altcoins, the restart will be harder. If the project once took the popularity and it suddenly died, there's almost no coming back from it. But we want to hear it from you op if what happened to this discussion or to the project that you are interested in.
You have started a thread and for sure that you are eyeing for a project that you think has the potential. It's just a matter of management in your eyes.
Bringing back dead altcoins would mean a very hard task since you will be working again in a long process and yet no assurance if it will end sucessfully. I'd rather advise you to start a new and potential project and build trust on the investors because it might have bigger chances to make you profitable in the end rather than managing a project that has been abandoned already because of some serious issues.