Something important that hasn't been mentioned is the reason they were called Slave to begin with. In the Japanese version of the game, weapons contain flavor text which has been left out in the Global version. For the Slave weapons, the text is: ''A sealed devil weapon from an early era. The user's hardships will call the power of destruction sealed within.''
In any case yes, censorship of video games sucks and I stopped playing the game. Not entirely because of the censorship but it was a significant enough reason.
The game has its moments and is fun sometimes, but I ultimately got bored of it. There's always this shallowness I find in MMORPGs (though I suppose PSO2 is more technically say... an online RPG ), in general, so I'm not apt to play any of them anymore. I suppose PSO2 was an exception because I've played a bit of the older ones and liked them, so thus my interest. I'm actually currently playing through all the older ones including the ones made for PSP.
I suppose perhaps the renaming of the Slave weapons to Raven can answer our questions now about the other changes and censorship. It seems to be politically motivated and Sega of America is HQ'd in Irvine, California, so it's not really a surprise.