Those problems would have nothing do with the UI. SkyUI is mostly done outside an editor from what I understand. The UI is XML if I remember correctly. I do not follow the UI discussion as the stock one is fine for me since the patch. But, I don't play in an ultra wide resolution. I can only imagine how weird it must be if the UI is stretched across a set up like that. I also don't know the reason why Bethesda does not make the UI scalable, and perhaps it is the reason the SkyUI folks have not done it yet.
I never said the CK problems had anything to do with the UI! (Edit: On reflection, maybe I read that wrong and you meant the game UI - or not!)
I have no interest in SkyUI - other than a wish to know if the makers are going to add a true widescreen fix!
As I said, 'The 'extended' preset is great for the CK* as it happens!' and to be truthful the 'eyefinity' preset is good for CK too. I prefer CK in extended as it is easy to have full screen CK on one monitor, full screen render window on other and use the third screen for my web browser for tutorials or such or run Skyrim alongside the CK.

When not played in widescreen, the game UI is great. Personally, I prefer it to SkyUI and that is why I do not want SkyUI.

The CK issues I and others have found have nothing to do with how the game UI is displayed or the game is played - save for the interaction between game, mods and CK.
The game Skyrim is great. The wide screen issue* is just a real let down for some.
The CK is great but has totally different issues to the game - it is 'early days' and I'm positive about the idea that Beth monitors user issues and acts on them - as can be seen through the Skyrim updates so far.
EDIT: Forgot to say - thanks CCNA - your input seems to me to be honest in the sense it comes from a different perspective and is greatly appreciated. And, yeah! The scaling issue makes Skyrim menus in ultra wide / widescreen / multi monitor and such look really weird!
*See below.
For any one that does not understand what the 'widescreen' issue is I'll set it out.
When I and others say widescreen we are maybe confusing some as we do not mean the widescreen aspect ratio options in the game launcher options. Rather, we mean multi monitor setups such as my ATI eyefinity 3 monitors set up in landscape side by side (3*1) or similar Nvidia surround. As I understand it 3*1 is a common setup with multi monitor users but other configurations with more monitors are available.
When running the game on a multi monitor rig with the monitors being exact duplicates of the primary monitor, you get three (in 3*1) visual instances of the game - one on each monitor. This is useful to some and silly to others! No fix need here.
When using an 'extended' configuration of multi monitors where two monitors extend the desktop from the primary monitor, one monitor shows the game (fantastically) and the other monitors can be used for something else - as I say, this is great for running both the game and the CK together. No fix needed.
The problem arises when switching the monitors to surround (nvidia) or eyefintiy (ATI). In this case, the computer treats the three (or more) monitors as one big moitor.
When using surround or eyefinity the game looks amazing and, in most cases it seems, plays wonderfully. That is all well and fine until you try to use some of the in game menus or map or books for example. In widescreen / multimonitor the UI for such menus etc is scaled incorrectly and as a result the menus etc are either 'zoomed in' or squashed - in either case the UI can (and does) become unusable as some information cannot be seen and / or menu options are off screen and difficult to use.
The guys at WSGF (and others) have released fixes for the scaling issue seen in multi monitor set ups and these fixes work great until Skyrim is upgraded and the (now old) fixes are useless until they are upgraded.
The general sentiment in the widescreen community seems to be that if third parties can fix the widescreen issue then Beth should be able to and not make it so that customers have to go to a third party for fixes. It is really frustrating for some that each time Beth updates skyrim, widescreen becomes unusable.
This problem of lack of widescreen / multimonitor support for Skyrim has nothing to do with the CK or SkyUI or the graphics card manufacturers or drivers. The problem is a Skyrim scaling issue. And has everything to do with the Skyrim UI.
http://www.amd.com/us/products/technologies/amd-eyefinity-technology/Pages/eyefinity.aspx
http://www.nvidia.co.uk/object/3d-vision-surround-technology-uk.html
http://www.nvidia.co.uk/object/3d-vision-surround-technology-uk.html - The whole thread is interesting but post #25 shows the issue I describe in images.