Is this guild or race affected?
Don't goblins already have a stat edge vs dwarves in dex bonus?
EDIT:
Personally I do not like this solution thematically.
A disciplined warrior does not benefit from longer lasting equipment.
He benefits in fights.
(An example could be the elite troups UK landed at the Falkland Islands during that war. Very few, but HIGHLY disciplined troups, vs the argentinian recruits who had little or no combat experience. That is disciplin in action.)
How about a small edge vs groups of monsters?
If you fight many trolls/orcs/haradrims/whatever you gain something in the fight vs those with less DIS.
Maybe a little defence/parry or maybe the less disciplined warrior looses def/parry/whatever vs many opponents? And the disciplined warrior does not lose as much.
Yes, that would be a nerf, but if it hits all in the game that might not be the worst thing ever done.
Exept that it is a nerf.
But ofc, this solution with longer lasting eq is at least one solution to an otherwise pretty useless stat.