i would perhaps start with the increase in large enterprises and multinationals - global competition, as these generally cant exist without financial markets.

Financialization of the economy is captured through a few indicators mainly market capitalisation and debt-to-equity ratios where the intermediation of saving to investment becomes a dominant function in the economy. I would say heaps has been done in this regard, but it really depends on a narrow research question you may have. I can personally recommend one of my papers: "Financial development shocks and contemporaneous feedback effect on key macroeconomic indicators: a post Keynesian time series analysis. Economic Modelling, 29 (2). pp. 487-501."

Thank you for sharing your idea