It may not be in the long term, but moving to price targets may come at the expense of price discovery. This links to the second complication: balance sheet policies can mitigate certain facets of the safe asset shortage, but they might exacerbate others. In particular, balance sheet policies have been stimulative by swapping central bank money for assets with duration and credit risk.
For capitalization, the definition of capital should be narrowed to include only truly lossabsorbing items such as common equity. Ideally, one would like differentiate with different weights not only the type of asset in general but the specifics of such assets – for example, a mortgage for a low-risk customer should not absorb the same capital as one for a high-risk customer.