[Ray2064]

That more has to do with LUC being a generally useless stat that you tend to only build to be able to crit (sometimes) , or to use one of the arguably best elements in the game. Maybe if it offered something like Inflict or really anything of value.
STR might be a strong stat in a vacuum, but it's pretty much been established it's fairly detrimental to anyone who tries to crit while statting alongside it. It's more akin to offering it a multi purpose than just giving it a massive amount of buffs.
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By buffing LUC's crit rate outright, you're also buffing VAs and gunners' which aren't really in much need of a buff and already somewhat comfortably stated. The gap between GUI and STR crits remains mostly the same.