Hmm... I have just been playing through arcade on easy mode. I think it takes me about 5 mins total (fight time is right about 4 minutes and loading screens take the rest of the time) and nets around 800 pts. That translates to ~ 9600 pts per hour.
So if you can go fast (focus on quick ring outs), I think that the easy mode arcade is actually a better route to go.
Just my opinion though... your method does sound like a good alternative. Both methods would get kind of annoying / tedious, so pick your poison.
100% Completions: 40
Retail: 17 Including: Alan Wake, Assassin's Creed 1 & 2, Fable 2 & 3, Prince of Persia & PoP: The Forgotten Sands, Red Dead Redemption, Soul Calibur 4 & 5, Tales of Vesperia
Arcade: 23 Including: 1 vs. 100, Alien Hominid, Bastion, Carcassone, Castle Crashers, MtG: DotP & MTG: DotP 2012, Plants vs. Zombies, Portal, Trials Evolution