I am in full support of Haks (had to download then to get on as it is). They can be intimidating to some, but like people have said, it will weed out the non-hardcore types. It will limit the player base, but it will make the ones that are here more personal in a sense.
To somebody's comment about d20 Modern being broken, I cannot agree with you more. After trying it out for a few mods, it was more annoying to play than anything. But I am a fan of the content, it just needed to be executed better.
Guns in FF-X is a stable to the cannon material. Hell, guns have been in the FF line of games from WAY back! I know they have been in since FF-4 (That is the U.S. version of 2). It may not have been personal guns, but the Red Wings and the other vehicles had cannons. But in this game, no guns = no al bed. Not very FF-X.
One set of tools that is more client side that I have played with (as a player not builder) is the SIMTools. Very fun. Not sure how it would interact with what you have here. Just adding my opinions.