It seems that until they remove the weapon restriction on Stunning Fist... You'll just not see a monk (unless it is a splash) using weapons.
Short sword use! Oh yeah! I can go from 8(D6) to 2d10!!!! Sure my crit goes from 19-20 to 17-20. However without the 50% (Or 80% if you're LD) damage boost of a stunning fist, and losing death touch, and paralyzing touch, and unbalancing strikes.
So, lets see, I lose > 50% damage, I lose sneak attack, and I lose death touch.
Yeah, why would any monk ever use a weapon... Ever ever ever?
What if I'm fighting something I can't stun/sneak/death touch? Like undead? Zombies? Before vorpal strikes, when a slasher would be nice?
I think if they removed the handwrap/empty hand restriction on stunning fist, you would see monks more likely to branch out, and maybe use those Ninja skills.
In the Lamina preview, they add 30% stun damage to the Ninja tree... So, it's even less attractive to use weapons. I guess it's just there as flavor. Nothing more. Of course currently poison application doesn't work with Vorpal Strikes, (even if it says it should).