My 05 WRX had that problem and my 13 WRX is better but I can tell it will eventually be the same issue over time. Its worth it once I'm moving forward and that boxer rumble begins.
I also do the shift dance but am curious to try the double clutch method. Both aren't detrimental to the tranny/clutch right? I use to mash my 05 into reverse and I KNOW that was bad for it lol.