I could add a web.config setting in the next release to make it possible to turn that feature off but in general I don't think a mistake in layout.master should be allowed to completely crash your site which it would do if we did not have handling for it. If I add this setting and you turn it off in your site and forget about it then someday someone will make a small change and accidently bring the site down. If something doesn't look right in your skin it is a clue that perhaps something is wrong in layout.master and its best to review the log to find the error.
Note that we are not loading a different skin, only a different layout.master file, it is still loading the css from the skin.
Its very easy to make mistakes in layout.master that cause errors, copying and pasting something with a duplicate id on the control will do it for example or leaving out required things.