Later on in the day I ended up finding some Jaina vs. Rook tech that is... Problematic. So at the time, you probably could have beaten me. But once I discovered the forbidden tech, it seems like a 9-1 or even 10-0 matchup.
However, @CWheezy is probably correct in saying that if Rook can get in a little easier, the matchup becomes heavily favored for Rook. So it's a weird situation balancewise where the low level play in the matchup is currently Rook favored, but the high level is Jaina favored.