Oh, I agree with that. But then, if a user is delving deep enough into templates to have any use for escape characters, they're ipso facto more or less programmers already (at least scripters).
I don't know about that. It's not that unreasonable to except a non-expert to want to pass a table as a parameter to a template. Consider an infobox in an article and there are multiple things that should go under a particular heading, the user decides to put them in table and does so in the obvious way. Everything breaks. That's a bad thing. (Of course, that's how it is now, but implementing escape characters isn't really an improvement, since most users won't know how to use them anyway.)