I fully agree. Though I have seen multiple use cases where people were complaining about things working smooth with other hubs and not anymore with HE. This is almost always due to adding more devices from different manufacturers to one single hub, in this case the HE. It's inherent to the versatility of the hub. And therefore I think such a tool would be necessary. Since @bravenel has said before is the hub more then capable of handling the processes, I think this wouldn't cost that much processing power (though I might be wrong).
And yes if there were any out of the box plug and play external device on the market (within reasonable cost) I would buy it. But the only options I've seen is with firmwares on dyi devices (I might miss some knowledge on a device that does do is out of the box) but since some of the other hubs out there are having such tools I don't think it's such a bad idea.
It wouldn’t .. The main thing would be Human Resources not CPU resources.. If they had infinite human resources I’m sure all this would have been done already...
That other hub in your first post was many times the cost of HE. The Zniffer is not hard to build and the software is installer grade. If you are experiencing issues and willing to dig, it is worth the effort.
If this won't be incorporated I will go that way in about 6 months I think. Though I might prefer to go the zigbee mapping first since that is my personal biggest mesh.
I fully understand. And I would love to add something to the table, though my programming skills are not worth pursuing. But if someone would start a Kickstarter like project to make this happen I would definitely pay up. But I do understand that money isn't everything either, since the resources are often hard to find anyway.
This feature is also not something I'd expect in the near future. But I hope it will be something somewhere in the future... 
I doubt this will ever be integrated as that would require another z-wave interface specifically for sniffing. It can't work both ways as a controller and sniffer it's an either/or which is why it requires buying the new stick to do it yourself.
for an easier route you can buy the Z-Wave Toolbox which is a self contained box or you can buy a Z-Wave dev kit which includes a controller and usb stick already pre-flashed as a sniffer but this is more expensive.
Are you able to get much utility out of the Toolbox?? I don't.
Zniffer is much more suited to my mind.. or I'm completely missing Toolbox's features. 
I'm pretty much ready to put the Toolbox on Ebay. 
Is more capable.
The toolbox is just a easier path to sniffing. I haven't tried it with the newer software. I should pull it out and update it. I'm been contemplating ordering a CIT to try out but I just can't justify the cost when I know it's not going to do more than zsniffer....
Don't be a smart guy! You know a hub is a controller, not a repeating device or end device! 
Taking Z-Wave out of the discussion, since the example @frits gave is for Zigbee, I would have to disagree with the idea of dumping time and resources into fixing the issues of old technology. Zigbee 3.0 is out and will grow in popularity. Future controllers will incorporate Zigbee 3.0 radios, which handle things differently. It's doesn't mean the basics won't still apply, but the approach and required platform and apps will be different. Investing in the future instead of spending all your time trying to fix the issues of older devices is the best way forward in my opinion.
Expecting Zigbee 3.0 in future hub revisions would be my best guess as to Hubitat's planned direction. But I don't have inside knowledge of that. Total guess.
@frits create a post and invite as many of your community countrymen to discuss sharing the cost of some of the tools and then mail them back and forth. The tools aren't something you will use on a daily basis and perhaps only once. Being able to share your findings especially as it applies to specific available devices would make for a tremendous resource.
Something that would be useful to me is just a simple map of the mesh. Zigbee and Zwave. So if I have a problem device, I can see the routing.
No it wouldn't
It doesn't have to act like a sniffer to give you details on your mesh, signals from nodes, and statistics and neighbors
Really? for the sniffer part? I know it can dual purpose and give the RF and noise/interference etc as several systems provide that info. However as for the sniffer that's a different firmware used...ahh.. wait. I'm still thinking of zsniffer and usb stick... so could it be implemented in parallel with controller?
Zniffer is promiscuous ie. not network specific. Obviously the Hubitat Radio must be network specific. But it better hear all the in-range radio traffic for it's own network. 
The question is about getting access to that 'stream'.
ooooh.. a new Z-Stream API? LOL
I have a few devices that will just not pair unless they are VERY close to the hub. Is it better to bring the hub to the installed device or the device to the hub? Or doesn't it matter.
John
Whisper Pairing is not currently in vogue.. but once it was and if you are Joining one of those.. yes, whisper distance is required... otherwise no.
Happened to read recently in this thread the feature set of Z-Wave 500 series (Z-Wave Plus) Zwave and zwave plus and was surprised to see that Network Wide Inclusion didn't become a standard feature until the 700 series. So it would be necessary to pair some devices (even newer Z-Wave Plus ones) within radio range of the hub depending on their feature set (not all, but you'd need to probe the specs to know).
I've always been puzzled why inclusion of the Z-Wave Plus repeater in the Iris V2 Plug fails unless done very close to the hub. Likely it doesn't use NWI. This is significant since it can effectively bork NWI for the mesh when used as a Z-Wave extender (it won't repeat NWI frames). Could explain a lot of 'fails to pair in place' issues even with the Z-Wave Plus devices that do support his feature.
Which home automation systems work perfectly? My only real experience prior to HE is with SmartThings. I think they’re still working on being “good enough,” forget about perfection.
I've miscommunicated that. I meant branded systems like hue. Where everything works out of the box. People are expecting that (wrongfully) of HE. A mesh map or analyzer could help them understand how it works when you combine different kinds of devices from different brands.
