maybe look at changing weapon feats (such as weapon focus, weapon spec, improved crit etc or any feat that requires a choice of weapon (slashing grace etc) to a base of weapons.
such as baldurs gate 1 and DDO do. so instead of picking weapon focus longsword and not finding any good longswords etc that you would choose say weapon focus “large slashing” or “slashing” “large sword” or “sword” etc and be able to apply your weapon focus to longsword, scimitar, greatsword etc
when unlocking an exotic weapon proficiency it would then be added to its appropriate group such as bastard sword and falcatta would be added to “sword” “slashing” “large blade” etc and fauchard would be added to “polearms” etc
one of my charatcers in beneath the stolen lands has weapon focus, greater weapon focus and improved critical greatsword, yet i havnt found a single greatsword yet and im on floor 20something and everyones level 12
he has a masterwork greatsword, +2 shock falchion, +1 cold falchion and a +1 cold oversized bastard sword. including the many other falchions found and sold, but no greatswords whatsoever. the above system would allow the falchions and oversized bastard sword to be used with his feats and not have them wasted
feats such as aldori dueling mastery should stay the same ie require that specific weapon