Financial Stability Board and Financial Services Authority have already raised concerns what with emergence of synthetic ETFs, inverse, or short, ETFs and leveraged ETFs. In particular, there are concerns with synthetic ETFs which depend upon a swap with parent bank to track return of an index against collaterals which considerably deviate from the index being tracked.
I expect macro-prudential policies to remain an important policy tool in years to come, though how much they are applied in a temporary manner or via permanent standards will be a topic for future policymakers. Debt-to-Income restrictions to my mind are an important and probably better tool than LVRs, but perhaps a mix is best.