I don't understand the dilemma. I, too, have a launch "fat" PS3 and also awaits the PS3 version while running my CE on my limping computer. However, are you asking "if" it'll be worth it to get a newer PS3 just for some performance boost?
From my understanding of the PS3 evolution, the slimmer it gets the more issues it ends up having with regards to PS2/PS1 compatibility along with the "play too much overheat" myth.
A lot of the PS3 freezes and hang ups has to do with the actually programming in the disc and the version software that your PS3 is running on. So from a fellow PS3 user with a tight wallet:
don't buy a new slim and sell your launch-date ps3 @ a loss.
But then again I havn't seen gamechanging performance from the slims. If someone else has more experience in that topic, please feel free to refute my advise.
And from what I understand, the post 6month launch built PS3 all had the emo-chip removed from its MOBO and software emulation came to be for ps2/ps1...which made ps2/ps1 games compatibility tank if you had the original discs (still rocking my Legend of Dragoon, MGS, and FF7) soooo really, I doubt a PS3 specific game like FFxiv would matter when it comes to PS3 performance across the board.
Core2Duo E8400 3.0ghz, 4gb DDR2, 1gb Radeon HD4650
NVIDIA® GeForce® 7100 and nForce® 630i
Orangejoose 80dk(A), Dichterling 80druid(A), Kocikowski 80pally(A), Rosencranz 80hunter(A), Dicht 80druid(H) -All Retired 2010
Dicht 70drg -Retired 2009