Nancy Springer wrote the terrible Fair Peril; I haven't read anything else of hers, but the faults of that book weren't the sort that I'd expect an author to grow out of.

Conversely, the faults of J. Gregory... er, Greg Keyes' Waterborn et seq. are the faults I'd expect a writer to grow out of, and I've heard vaguely good things about his new stuff, but haven't been motivated enough to read it. So you should, and report back.