Buy Panny plasma or wait?

[x RadicalAura x]

I currently have a 50" LG 50PA6500 that I bought last year. With the news of Panasonic halting plasma production in March, like many, I'm now considering the purchase of a ST60 (either 50" or 55", price permitting). My questions are:

1.) Will I notice a big enough of an improvement coming from my 50" LG plasma to a ST60 to justify the purchase? (I would assume the answer would be yes, considering the stellar reviews)
2.) Is it a wise investment decision, given the development of OLED/4K displays? Would it be better to stick with my 50" LG plasma for 3-5 years until OLED/4K TVs are more affordable and refined?
3.) The cheapest price I can find a ST60 right now is $999.99 for a 50" and $1349.99 for a 55" through Sears. Is that an fair price? Is there a chance the price may decrease more in the coming months or is the risk of waiting and having them all sell out too high?
4.) Considering I spend ~50% of my TV time playing PS3/PS4 games and the other 50% watching Blu-rays, should I be concerned about the input lag? I'm not necessarily what one would call a "twitch" gamer, but has anyone else with a ST60 had issued with gaming performance?