Well, it's only undesirable due to the current six month thing for an MPC. But then, hasn't the constant argument in favor of that been that it's a 'soft' time limit, or whatever? Since hags, by their function, are schemers and long-term game planners, who pull the strings and meddle with politics, you could probably get plenty of extensions if you were portraying a coven that was meddling with stuff behind the scenes.
Of course, that's assuming that behind the scenes, string-pulling MPCs are still allowed, and the arguments of the server only wanting 'burn bright, die fast' MPCs to serve as little more than chopping wood for the playerbase are entirely unfounded - so you tell me.