I don't know enough about borked up Dark Suns stuff, but I can't imagine a special ability that gives you more BAB than your character level.

Other than that, you can't get Weapon Specialization unless you have 4 levels of Fighter or a specific PrC that gives you access to it.

Also, the Deepwood Sniper class gives you "Keen Edge" at level 6... but never says what that means.