Devo max for cities? or following Whitehall's trail of breadcrumbs?

Today I’ve been reading the City Growth Commission report and listened to the live webcast (can replay it here) have a few observations and key questions.
Perhaps playing a wee bit too much on Whitehall’s pitch? I’ll have to state – I’m pro-devolution in terms of I think there is definitely something in it – some budget, powers and responsibilities should be devolved from Whitehall to cities – as some tasks are best driven and administered locally that currently aren’t. However, the CGC report to some extent plays to the current Whitehall policy environment with the language of ‘proving ourselves worthy’ of devolution.
We should abandon the ‘precautionary principle’ or the “you can’t prove devolution would work” vs “we can’t prove it will work or not unless you let us try it” debate! The precautionary principle is deeply imbued in Whitehall – it means – we won’t act unless there’s overwhelming evidence of need. If you have never tried something, you will not get the evidence.
From the event today “We’re not ready!?”! its an excuse for Whitehall to sit on their hands in my view. Instead of opening the door a crack – we should be pushing our government to declaring “in 12 months we’ll be devolving adult skills budgets in their entirety to combined authorities” – get ready for it, its definitely coming.
Policy suggestion: Whitehall should be accountable for helping local powers “get ready” – instead of asking metros to ‘prove their worth and capability’ – there should be a duty of Whitehall to develop the capacity locally – training, support, designing the legal frameworks and systems
We could wipe HM Treasury from the equation by establishing a statutory basis for balanced budgets, or for maximum deficit management before emergency powers kick in.
There are some more useful policy levers to devolve which might be more applicable to different places. For example – allowing cities such as Glasgow to have more powers over welfare programme design and administration might help them address some of their challenges a lot better than the current national system, such as those followed in some US states.