thank god for reverts, but an idea just hit me.
if you wanted variety in decks and didnt want people bothering with different guard types, why not halfass the two systems? have a universal guard that can more easily be lowered and raised while having the 4 colors system as well. make it where its easy to keep certain color guards up/lower opponents color guards if you specialize in them, but not if you dont.
have the universal and color guards work in conjunction, with the damage dealt modified by the average percentage of the two that the attack hits for. E.G.: punch hitting for striking(green)+ universal. green and universal openings both come into play against it.
people that dont want to bother with guard types will go for the half damage that fully opening up the universal guard would allow. whereas people that want to use the colors can experiment and figure out ways to use them effectively.