In all seriousness, obviously there's no way Steph was a better fighter than Tim. However, it was frequently observed in those days that Tim was NOT a natural athlete and had to work harder than Dick ever did at the physical stuff, while it was implied pretty heavily that Steph was, in fact, naturally athletic. Accounting for the obvious physical differences between men and women, her ceiling was probably higher athletically; just as Tim, being a genius, is always going to have a higher intellectual ceiling than Dick or Steph (or Jason or Damian), even if he's not always smarter than them at any one individual point in time.
If you're a baseball fan, you'd probably liken it to a player who has lots of tools and potential, but came from a tough economic background, didn't start playing ball until high school, and lacks some polish. That player may not ever make it in the Bigs... many such players don't. But if they ever do manage to put it all together (like Stephanie did as Batgirl), watch out.