What the heck, if it was good enough for PL/1...

It would still be parsable indeed. A keyword available in a context would then be something new in the language.

Choice of syntax is important, though. It's all very well to come up with an "insert syntax here" proposal that has some big obvious benefit, but if you can't actually come up with a pleasing syntax for it, then it won't fly. So it makes sense to consider potential syntaxes along with other aspects of a proposal.

Of course the syntax is very important, that's why we make a list of pro's and con's about each syntax. However, people also want to know if the feature is useful for a lot of users. So, should we do that list somewhere ? :)