The interplay between wealth and income is a hard one to navigate, but I think important.
Part of the economic story of the last generation (IMO) is embedded in this interplay. Financialization is largely the process of turning future income into current assets. EG, I buy a house, get a house and a mortgage. My wealth is net 0. One house owned. One house-value owed. Part of my future income is now someone else's current asset. They also net to 0 change (mirroring my balance sheet). Yet obviously, something somewhere has changed.
Lending and creating money are interlinked, as is inflation. Monetarists tend towards macroeconomic thinking, and default to regarding of inflation as a single thing. In reality, inflation is microeconomic. More real estate lending, higher real estate prices. Also, "inflation" as an actual phenomenon is not simply devaluation. It is all price and market size increases, including increases in "quality and quantity". More real estate lending, more/bigger houses. Another striking example is american universities. More student loans, more expensive tuition, fancier uni experiences, more students. All that is "inflation" in the "consequences of money supply^" sense.
Another aspect that I would be interested in seeing approached is "inflation by income level." I suspect that this is increasingly important, especially because of housing cost fluctuations and trends. If 40% of your income is spent on housing, a 25% increase in house prices represents 10% inflation assuming all other prices remain constant. Similar calculation for college and such. Your inflation could be 5% pa, while the average inflation is 0%. This is happening now where I live. People's spending habits are very dependant by social-wealth class, so I think it would be worth trying to generate class specific inflation rates. I expect income inequality growth would look faster this way.
^I'm alluding to Firedman's "Inflation is always and everywhere a monetary phenomenon" though I've defined inflation differently to the macroeconomic/monetarist standard which explicitly excluded increases in "quality and quantity." I think it still holds, as long as you swap "always" with "often" which might even be necessary for Milton's.