???
Let's just review, not b/c I think you didn't so something you should have, but simply b/c I hope you didn't simply so that you can get better performance.
Before you flashed RC2, you did full wipe and wiped Dalvik? You upgraded to latest radio.. 2.15.00.07.28, you wiped again, you flashed RC2 then flashed new Gapps package?
You are using Amon Ra Recovery?
You disabled Google Talk?
Did you flash a Snap kernel of any kind?
Oh, also I am using Set CPU and that may have a major affect in my performance vs yours.
Set CPU setting:
Max: 1113600
Min: 128000
ON Demand - Set on Boot
Profiles:
Temp>50C : MAX/MIN: 128 (Priority 100) POWERSAVE
Screen Off: MAX/MIN: 245 (priority 97) POWERSAVE
Battery < 25%: Max: 499 Min: 245 (Priority 85) CONSERVATIVE
Chaging/Full: Max: 1113 Min: 768 (Priority 80) INTERACTIVE