The alternative is an OC session, where the mechanics are used but the characters are different. In that case, if you did use a Rationalist Premise, it would almost certainly end up as leisure reading for people who are already familiar with the concepts (as opposed to leisure reading for people who are familiar with the canon but not the concepts). It would not be Useful.

It would be interesting as entertainment, given the existing composition of Homestuck and the sheer ease at which the game can be twisted out of recognition, but most of the reason I don't is because I can't model people like that.