Oh, c'mon! Really? Why bother to release CK at all?
Clean install of Skyrim gives me a random CTDs and same problems as the modded/tweaked one. Game is still playable, but I have to save way more often. Constantly keeping in mind "Don't forget to save, don't forget to save" is a total killjoy.
Since the Fallout 3, first reaction on the unstable gameplay is to make a clean install and reset all settings to default. But this helped me a couple of times, while third-party software/ launchers were a bug-removers and gameplay stabilizers for... damn, for months. I prefer stability over performance, and 1.3.10 was unmatched by this factor. Now a lot of people reporting sounds skipping and CTDs return. No, of course it has nothing to do with a patch.
"A CTD! I saw a CTD! It ruined my two hours of gameplay! - What is it now, gamer? It all caused by your mods, not the latest patch"
You missed the point entirely. Third party stuff can cause stability issues with official software releases. Not because of the dev of the official release, as their work is fine. It's up to the third party to ensure compatibility as they are the ones that are developing their software. The official developer is no way responsible for a third party script that, for instance, has a function that crashes the game on purpose every 10 minutes or so. Also, the third party could be misreading a bit. That is not the responsibility of the official developer at all, as they aren't the ones who are writing the other stuff.
Mods and other third party software are in no way the responsibility of the official developers of a piece of software to ensure compatibility with. It's up to the third party to ensure their stuff works with the current release.
As an example:
Someone writes a file manager to work with Windows and they do not work with M$oft. They release the file manager without testing it and the program has a fatal flaw: it tends to delete the system32 folder. M$oft is not responsible in this case. They just provide the API and libraries.
The reason for not testing with mods and other third party software is to ensure that one is testing the game, not the additives.