I believe Raymond Hettinger now considers that a mistake, and wishes he had gone with a trailing underscore (param_) instead. A trailing underscore is just as unlikely to lead to a collision, but less confusing.
It takes a bit of manual juggling, but if you take kwargs anyway you could inspect them to check for the old-style parameters, and use them if they're present, perhaps with a warning. That way you don't have to break compatibility.
