That sounds like a very fun project. There is of course the technical work in identifying unused code and resources, a data science framing where statistical questions regarding bloat could be assessed, a process framing component where tooling and dev-platform interactions could be incentivized toward reducing bloat, and and economics framing where structural changes in Play store could change dev strategies toward bloat. Someone in charge of leading such a project has a lot of options available for analyzing and solving the problem, none of them mutually exclusive.