Comparing the Harrier to an A-10 isn't a very good comparison since the Harrier is much closer in performance to a Hornet than it is to an A-10.
Eh. Yes in thrust to weight and acceleration. Neither of you guys were built for Air to Air. A-10s can rate around a circle really well- the whole straight wing and low wing loading allows them to be really good low speed turners and gives them fairly decent nose authority- nothing compared to the alpha control of the Hornet though.
I also think you over simplified what a DCA vul entails. It's a lot more than running a couple of timelines. My last air to air flight in the hornet RAG was a 4vx with multiple groups across multiple altitudes and airspeeds. My lead was on his Div Lead upgrade and was pretty tak saturated. When they only have to get one guy by you to win the stakes are fairly high. 4/0/2 and gun sometimes wasn't enough. I can't imagine trying that 2/0/0 and gun, and in a jet not built for that environment.
IMHO everyone should be wearing JHMCS and carrying 9X's if for nothing else than the defensive capability. The AF is even looking to put them on Reapers just for that.