NurseyPyro is pretty good for pushing out of choke in gullywash (into mid and from it) and pyro is good for badlands spire when pushing out of last. Any map with tight chokes pyro would actually be pretty decent for pyro, but those two things I'd argue is better for pyro than even the stock classes.
Any map is decent on pyro (except via) as long as you replace the pocket soldier and get enough healing. However, its fucking shit when pushing out of badlands last because u can't get onto spire and if you fall down you can't get back up again.