could be specific to the classes or something, the dw classes having thinner lightsabers, and the tanks and 2h dps classes having a thicker, stronger lookin lightsaber.
either way, cant wait to see this game!
Kotor already had crystals with higher deflection or higher damage, depending on your build, but they didn't change the visual effect. I don't think it really suits, I mean it makes sense that a wider emitter would make a thicker beam, but it's not documented anywhere in canon so far that I've seen.
On this case, its not wider or bigger. Resized blue lightsaber so it looks to be in same level as yellow one (on height, no widing or thinning done) and the pic under is blue top of yellow with 50% transparency.
Its just "optical illusion" where yellow is so strong color even on the ends of it makes it look wider. Blue one goes "white -> blue -> light blue" while yellow goes "white -> yellow -> lighter yellow" and since yellow and white are pretty close it makes it look wider because the contrast between the two colors is different.
I think what would be cool is if saber shape and length and all that were changed with weapons. Maybe replacing a weapon gets you a different shape? Then pop your color crystal in too! Something like that seems to me like a fun way to change shapes around.