If you're currently displeased with the PQ of videogames on your Panasonic plasma, you won't find any better PQ on the newest Panasonic plasma's with those 30fps capped xbox/ps3 videogames.
The framedoubling issue stays with Panasonic as they dont have the Samsung Auto Motion Plus AMP feature to interpolate/convert the 30fps to 60fps smoothly!
See post #9664 http://www.avsforum.com/t/1397245/official-panasonic-st50-series-discussion-thread-no-street-price-talk/9664
Even the upcoming PS4/Xbone probably most games will stay capped at 30fps with full hd 1080p, because of low gpu capabilty, gamedesigners will choose best 1080p graphics over framerate capped at 30fps!
Only the better pc videocards are able to handle 60+fps at 1080p.
Plasma's are best for playing motion smoothly with movies and true 60fps video/pc games, if you can take care/handle the IR precautions.
Computer/videogame graphics are better/best on LED/LCD, now with the latest generation Samsung native 120Hz/240Hz 3Dtv's with AMP Blur Reduction and Judder Reduction, both adjustable from 0 to 10 settings, you can finetune any 30fps games to gives the best smoother PQ!
Only hardcore FPS gamers can notice any input lags, since you don't even mention any 30fps framedoubling, you better go with a Samsung LED 3Dtv.