How do you control how far or to what extent the 'liquid' disperses? At some point, you don't want it creating shorts by contacting adjacent circuitry. Cool idea, but a lot of questions to be addressed with this concept.
Seems like this wouldn't work in more delicate circuits, such as those inside a CPU or GPU. The different material used to fill the cap would create resistance/inductance changes that fundamentally alter the circuit. This would have worked better for something like 80's electronics that didn't have such tight specifications.