The ambient light issue is quickly solved by using room darkening blinds. It's far from the brightest room I've seen with large plasma HDTVs.
Truth be told, I am not familiar with the 'flash lighting issue' or 'panel lottery' incident. Links or brief description you could share? It's true though that some panels are manufactured by different suppliers. And that can lead to differences. OTOH, all of these HDTVs have various nitpicky issues (even plasma). Some of them may happen to be more glaring to some than to others. YMMV.
Personally, you will likely be seeing more differences when you jump to the 8000 series than you would comparing a 55 w/ a 65 of the 7100. What else does the dedicated thread @ AVS have to say on this topic(?)
I'm just not seeing the viewing angle issue as something relevant for you in such a modest apartment/viewing space. It would be a different story if you had a huge room in a single family home. Or do you happen to have a thirty foot long couch hidden on the side opposite from the HDTV I see in the picture .