I suppose you mean the recent news about abandoning Unity and focusing on a gnome shell desktop for 18.04 LTS? Sure, it must suck for those who have invested a lot of their time and soul into Unity and are now losing their jobs.
Personally, having used fvwm, olvwm, afterstep, window maker, gnome 1, 2, 3, kde 1, 2, 3, 4, 5, fluxbox, unity, xmonad and a dozen more or less shorter acquaintances, my experience is that I can get work done on all of them. What the Linux desktop needs is not yet another reiteration of roughly the same concepts, but more elbow grease and polishing. Which happens when you have more users and developers. So with three of the major distros shipping with gnome 3 out of the box (ubuntu, fedora, debian) I think this will eventually be a net positive for the Linux desktop experience.
Thinks like hot plugging thunderbolt and having audio work perfectly, monitors readjust automatically, and variable dpi support. Actually so far ubuntu's been the only distro that makes it work well. This is the only reason I use unity.
I guess time will tell if your optimism or my pessimism is correct.
Pretty much every popular distro has this experience nowadays. Fedora(as a sibling poster mentioned) is indeed one of them and may I add, at least, twice as stable.
apt install ubuntu-restricted-extras, does it in Ubuntu.
On the other hand, although I understand your need, keeping the /home in a different partition and just installing the next Fedora release every 13 months does the job for the most part. And the installation(from a USB) is not more than 15-20 minutes.
Around 2011-2013, I used on my work(office) machines Ubuntu while I continued to have Fedora on my laptop.
Fedora not only did it have more recent packages, it was so much more stable than ubuntu that it was incomparable.
In general I find Ubuntu as the most unstable distro one could use :/
Also, dist upgrades are a bit unnecessary when you can have your /home in a separate partition and do a fresh install of the newer Fedora version in a couple of minutes.
> It also doesn't even pretend to support upgrades
How so? I installed Fedora 21 a couple of years ago and I've been continuously upgrading it up to 25. I've never encountered a single problem with the operating system itself (only with the NVidia driver, which is a major source of pain for all Linux systems, I guess.)This was certainly true in the past but hasn't really been the case for the last couple of years.
DIY: Arch Linux > Slackware
Compile It Yourself: Gentoo > BSDs
Friendly: Fedora > Mint > Ubuntu > Solus > countless other Desktop Env specific distros
Developer Focused: openSUSE > NixOS > Fedora > Debian
I want something that's a bit stable with more recent packages. FreeBSD seems to be semi-rolling release, comparing package versions in the 'current' release with that in the snapshot versions. Debian testing has packages as recent as I can use, but I heard it's less stable than Ubuntu and bad things happen too. I'm considering Fedora, but I prefer rolling release distros to fixed release ones (I don't want Rawhide for stability sake). OpenSUSE has older packages in its repos: PHP < 7.0, gcc < 6, ...
Now to your original question:
If you want bleeding edge packages go with either Arch Linux, Gentoo, openSUSE or Solus. I haven't used openSUSE as extensively I'd like to but haven't had any issues with it yet. The package format is a bit too much if you want to create your own packages though. openSUSE ticks all the marks in your checklist too.
Other than that I will suggest to keep your local dev environment as close to production as SANELY possible. Fedora and openSUSE are good bets.
Personally for rolling releases I've found Arch Linux to be the best (not because they are rolling release but because they generally keep the packages without any modifications from upstream). There is a huge selection of packages. But it suffers with the problem that it's not used in production and hence some issues can't be caught on it.
I've used Slackware before, and it was an easy look into the system; except that package management is a bit stressful on Slackware, and its packages are not so up-to-date.
I'm running a VM with FreeBSD now; how suitable it can be for a laptop, I don't know yet. Battery life matters there too.
Fedora looks good; I already have a Fedora 24 disc, so I might go from there instead of Slackware. openSUSE tumbleweed looks great too. I'll probably try it.
I can't vouch for the package breakages on any system other than Fedora. I've just had a single package breakage on Arch in over a year. It was fixed by simply moving a file and making a symlink.