Per others, I've put reasonably priced UPS behind my routers, HE, RPI and other hubs (e.g. Lutron).
This allows me to kill power for hours in my house across the board - be that for re-wiring, fixing something, installing something new, or even just normal power-outage.
But I do agree, HE could/should do a better job at recovery when it's power is cut.
At the risk of once again having to point out the absurdity of this, just what is it that you think can/should be done? It's easy to say the hub "could/should" do something, and impossible to actually do that in reality. So just what is it???
On your own, you could do any of the following very easily when the system boots (note, it is not possible for the hub to know that it is booting after a power outage as opposed to any other reason it might have booted -- which only increases the challenge; unless you think that somehow it should know that it lost power as a distinct case):
Being EE for many years I can tell you - internal battery is worst component to have in the device.
Except of course, for all these battery powered sensors (and even this is a BIG IF).
One reason is if you need to power down your hub for any reason (reset z-wave radio?). I remember having to do this (more than once) with SmartThings and it was a pain. With a UPS I have more control and can cover a few more devices nearby..
But, if the hub has a battery backup built in, it could itself detect losing power from the mains, gauge the battery status, and initiate shutdown on its own, assuming the owner has set it up to do so. I don’t understand why having the battery backup would interfere with you initiating a shutdown outside of a power outage.
Sure, I get that. On the other hand, being an EE for over 30 years, I can say that PC motherboard manufacturers seem to have perfected the onboard battery backed up real time clock. I can't think of of a PC motherboard that I have bought in 30+ years of working as a controls engineer for a Fortune 500 manufacturing company that didn't have have one. And, I can count on one hand how many of those batteries we've had to replace in literally thousands of systems over those years. The batteries will easily last 10 years, if quality components are chosen. Doubtful folks will still be using the same hub 10 years later, but who knows? 
Of course, the systems we buy are a little beefier and more rugged that a consumer grade home automation hub. They also cost quite a bit more as a result.
I guess my point is, a small RTC battery is not all that hard to implement, without adding a ton of cost to the system. I understand that Hubitat probably will not choose to add this, nor do they seem keen on developing a "Pro" level version of the hub, as that would require significant design and development costs, with a relatively small/niche user market, making it challenging to recover the up front costs. We can dream, though... 
For those who need tons of horsepower, choice of hardware, ultimate flexibility, and quite a bit more complexity, there is always Home Assistant. 
Perhaps. There are ARM boards with on-board RTC batteries. So perhaps designs exist that can be adapted with zigbee/z-wave radios for a lower overall design cost?
@bravenel Even that is not a real challenge.... I have a contact relay that triggers the setting of a hub variable when the power goes out. Then gracefully shutdown the hub after a delay. Then when the hub comes up (Location event: systemStart) I run a startup routine that checks the hub variable and does whatever I want to do (which in this discussion seems to still be undefined). Are there some improvements that "could" be made, sure. Is it anything that warrants labels like "weakness" "pathetic", "poor", nope...
For my experience with SmartThings - it was usually more often the case that I needed to physically shut down the hub rather than worrying about power backup. Besides a UPS can do other nice things like power conditioning if you have the right type. Thanks to the Ring Extenders I can pretty much detect and respond to power outages as needed now.
I'm really of mixed feelings with this whole internal hub power backup/ no power backup thing .. I guess I'm on the "no internal power backup" team for now.
Fun discussion that hasn't devolved yet.. though may be getting a tad repetitious.
I'll admit, after reading the onboard battery backup discussion.... all the way from :
"provide enough to keep the clock ticking"
to
"add enough to cover for 90% of the brief power interruptions we normally encounter"
to
"never mind you'll never package this with enough flexibility and duration as what I want/have"....
On one hand I'm thinking - don't go down a "build it in" path because there are better solutions off the shelf that could be integrated and sold as an option ( and HE should know what's going on/in that attached (USB style?) battery pack).
On the other hand I'm thinking - these days there are very few mains powered electronics (w/ processor, memory, and logic capability) I buy having either a) an important role or b) a measurable reset/reconfigure hassle, THAT DON'T COME with a slot for a backup battery to make it more user friendly.
Heck, the ole wall wart weather monitor has this and I've never had to touch the thing other than to change that battery. My HE hubs serve a FAR more important role. So yeah, I took care of it especially because some of the outages I experience are long and the power conditions sometimes spikey.
But for a whole lotta people, ...popping in a simple little battery would cover the 80/20 rule and one more slice of the fear & frustration factor in Home Automation.
$18
$26
Yes, those are fit for purpose here. And better for some of what I have set up. Good suggestions.
But now scroll back to the discussions where folks are talking about HE KNOWING about the state of the power and the reserve of the reserve power.... and the ability to take desired actions accordingly.
Ah, Hubitat Excelsior, $799.95 on sale... Market size: 4.
5
You guys are making my Friday.
Too funny. LOLOLOL It's the 95 cents that takes it over the top 
One could leverage the Canary Bulb app written for ST and then run a set of rules exactly as you outlined. This would allow a more automated way to determine how/why the hub rebooted.
I'm sure with the long weekend coming up @bravenel can intergrade this into the next release for full scale power recovery like the OP is requesting. Or they could always do it themselves. 
Edit: this actually sounds like a good idea to use the canary bulb app to trigger a rule to refresh the state of all my devices after a power outage.
Edit2: Done. Ported from ST and modified for Hubitat. Uses a canary bulb to detect the power failure and restores a set of switches to their original state. Triggers every 5 minutes or on hub reboot.
Speaking of which, I can go to Radio Shack and buy a battery holder for 95 cents. It shouldn't cost any more to add that to the product*
*I was once given essentially this exact argument when telling someone that what they were asking for wasn't going to be easy.
I suspect getting something ready for manufacturing and mass production is a wee bit different and a lot more expensive up front than going the DIY route.. but I have no experience with this other than buying into a few kickstarter projects.. 
Here's me, reading this and thinking....
If multiple smart people have been motivated enough to search for/create/or improvise a solution to some of the vary issues being discussed on at least TWO different vendor's platforms....and it is doable at a reasonable cost.....does this constitute something that:
a) every new purchaser is suppose to stumble with until they eventually look and find the right community developer written solution?
or something
b) a sharp "market proactive" platform would incorporate so that their hub was better than all the rest in all critical ways....and so that no one could ever have the excuse of being frustrated by this aspect of Home Automation with their platform?
Aren't there people that write reviews and make a big deal about these little things that nobody thinks about when they go buy something ....but that make a big difference when you start to use and rely on the product in a real life collection of "use cases" (i feel so young and hip saying that).
I donno, that's just my 95 cent observation
Here ya go:
Ported from ST and modified for Hubitat. Uses a canary bulb to detect the power failure and restores a set of switches to their original state. Triggers every 5 minutes or on hub reboot.
Download the Hubitat app
