[wnoise]

Even though it is a styling issue (I want about 1.5), you still need to distinguish the cases to the renderer. If you want different intersentence spacing than interword spacing, you can't just check for the presence of a period -- the rendered versions of abbreviations like "Mr.", "etc.", etc. need to not have two spaces after them. You either need a whole lot of exceptions built-in (which still fails for sentence that end with abbreviations), or to somehow mark the difference. Multiple spaces is still a nice source convention, because it's minimal and shows up approximately correctly.

(LaTeX does do simple finding of periods to support different interword and intersentence spacing. The recommendation is to use ~ after abbreviations; as a non-breaking space it also keeps Mr.~Whatsisname from appearing on two lines.)