Looks like the proposal that came up long before I got here is relevant again. Quotes as filter parameter delimiters? - #17 by TW_Tones (I personally like the parentheses idea, except for the fact that it seems common enough to use parentheses in tiddler titles, plus they could be often used in regular expressions just like [].)
As for figuring out the fix for the documentation… priorities… maybe one of these weekends…