all stops within the city are free, once you cross the river, they are free. that was always the case.. not sure that effects the volume going to the north shore for the daily commute though, no one lives in downtown Pittsburgh, no one lives near wood street or gateway plaza and needs to commute to north shore. If they did, they'd just walk across the bridge, it's easier.
I wont argue with you on your last few points, politicians playing politics, rooneys play it well. All I can tell you is that those last two stops, north shore and the one by Heinz, does not go unused.
If all things were equal, and it was between the T stop to Heinz or a line to Oakland, I'd choose the latter, no arguments there..