Even though there tends to be a sharp divide between vocal supporters of the 360 and PS3 (just look at the hornets nest kicked up on Metacritic re: Gears 2 and LBP), I still think Champions is going to ultimately set the tone for how successful the concept is received.
Media outlets will no doubt look to Champions as a benchmark moving forward - so if Champions is successful on the 360, expect a lot of positive talk once the Agency rolls around. If it flops, I expect the exact opposite, with a general buzz of, "Well, it didn't work for Champions, so I don't see how SOE is going to pull it off".
I still see this as "testing the waters" to see if the concept will float at all. If there were a genuine push towards consoles as a primary platform we wouldn't be looking at PC as the lead-off SKU at launch. That in mind, the idea comes down to an attempt at expanding the overall market rather than replacing the one that already exists.