Personally, I think there’s a point we’ve missed in the discussion so far. And I only point this out because I think the history is important, not to try to hamper suggestions to build on what we have today.
The original focus of Gadgeteer was to allow rapid prototyping. That means, quickly connect an assortment of devices you have, to a controller you have, and not have to write drivers for everything, just go to the application logic portion of the problem. It’s driven to help researchers solve problems quickly, no custom boards needed, and they can iterate on a problem quickly with little hassle.
The reason you want rapid prototyping is to prove the components can be made work in the way you want and that a commercial design can then proceed. Do you care if that uses more power than optimal? Do you care that you can’t power it in anything other than one state? Probably not.
And finally, once the research has been completed or the prototype done, the components can be broken down and reused. No more shelves full of dedicated hardware that will never see the light of day after the original work.
This is what unlocks the money, when someone says yes lets invest in that new tool/item/object. Then the hard work starts, building custom devices into a single unit, and that’s where power consumption and powering off unneeded devices etc becomes more important (and it’s the bit that Gadgeteer didn’t help you with but if you’re commercialising a product you would be able to draw on that expertise)
The scenario we’re all seeing now is that the commercialisation of Gadgeteer puts this capability in makers hands, and the same goals don’t always apply. Our projects aren’t always short term or research in nature, some times we really want to leave the “product” in it’s housing and use it for months configured in one and only one way. We use it to make the products that interest us. There’s also this IoT fad that’s coming along that is changing what we do with these projects. (yes, I know, calling it a fad doesn’t mean it is one ) And if we want to let makers take full advantage of this, yes we will need a way to be very frugal with power, but I also don’t think we need to be OTT and have everything trimmed to bare bones - it’s likely a few core modules that really would benefit from this that we’d expect to be needing in these scenarios (wifi or 3g modem, and if a sensor used a lot of power all the time even when not sampling)
The one thing I would like to hear more about is the “indirect” feature recently added in Gadgeteer Core, is that an opportunity to build an “isolator” module that can manage the downstream power? I guess the one gap I can currently identify right now is a re-initialisation process since many modules will revert to the default state and need to be re-init-ed if you chop power to them.