Mismeasuring Our Lives is an interesting read, though portions don't age well (most notably the sustainability section, which I suppose is at least a partial validation of statistical efforts in the most recent decade). The book is laid out in three key sections--suggested revisions to classical GDP measures, the adoption or privilege of measures which better capture human wellbeing, and considerations of sustainability, defined as the ability to perpetuate current levels of wellbeing and consumption through future generations.
The suggestions struck me as largely cogent, identifying issues like unmeasured changes in quality (biasing inflation upwards) to estimates of heretofore largely omitted accounts like household labor in the classical GDP section. Certain revisions to adjust for issues like availability of public goods are essential for "apples to apples" cross-country comparisons as well; GDP shouldn't change based on the provider of services (for example, health insurance) unless that change corresponds to differing levels of quality.
The human wellbeing and sustainability sections were necessarily more theoretical, though I agree that efforts to better capture factors like health outcomes, education, economic stability, social connection, political voice, and environmental externalities could drive better policy decisions. This data is necessarily normative, and preferences likely differ across a population, but efforts to maximize time spent on activities which correspond with human flourishing (self-defined through survey data) would be worthwhile. Given that the independent variable in this analysis is so subjective and that any composite measure requires a large degree of inference and judgment--particularly as it pertains to the weight of different dependent variables--consensus is unlikely to be satisfactorily achieved, though that shouldn't suppress efforts to move the proverbial ball forward.
On the sustainability side of the ledger, the authors' approach is an interesting one, considering a dashboard of measurements designed to identify where overconsumption or underinvestment may render future declines in living standards or consumption more likely. In effect, the authors seek to identify where current consumption patterns deplete existing "stocks" of human, physical, and environmental capital, mortgaging the future for present consumption--though the models they propose are necessarily subjective in that output prices (outputs of production, like pollution or environmental degradation) are rarely available the way that input prices (commodities used as factors of production) can be. Further judgment is required as scarcity or projected scarcity of future resources could cause massive swings in future prices of commodities that are relatively abundant today.
On balance, the book does a nice job identifying key areas for future research and introducing a framework through which better policy and market decisions could be made, though practical application is understandably limited. GDP is an imperfect measure, and the addition of satellite accounts like depreciation and depletion, offset by investments in human and physical capital, could underpin a more illustrative and comparative net account that better deals with externalities and flaws in the existing model. Probably the least developed and perhaps the most important idea ties to a two-part sustainability framework--one part tied to valuation (inputs) of environmental resources and the other based on normative assumptions that treats depletion and resource utilization (outputs)--which could flag where a country's consumption and investment levels collectively clip below a threshold where they're consuming their stocks of physical, human, financial, and environmental capital. This, in turn, suggests an unsustainable forward path for current levels of wellbeing.
I'd contend that half the battle ties to appropriately identifying, measuring, and quantifying these issues--the other half ties to effectively conveying them in a manner that's both digestible and actionable to the public. People are notoriously bad at dealing with long-dated challenges and those which are large in scope, so metrics like the EF's "number of earths" required to support a country's lifestyle are likely more resonant than even academically sound measures like net GDP adjusted for depreciation and depletion. In truth, this is probably the most fruitful path forward for achieving meaningful public buy-in--quantitative rigor is important for directing policy proposals, but effective marketing is necessary to achieve investment and collective action.