Wow, that does seem pretty lackluster
was hoping for something that would let the engi get further away from his sentry, not rely on it more
The fact that its a shotgun means you need to be pretty close to do anything more than a few points of damage with those crits, suppose it would be useful for when a spy comes along and tries to mess with your sentry, but its not like the wrench doesn't already insta-crit spies once your guns got a kill or 2 which makes this kinda redundant, hopefully there will be something that links together with this like the Targe and Eyelander do
The only real use for this off the top of my head is for offensive engis who place a lvl 1 sentry, let it get a kill, destroy it, and then place a new one in a new location and use the crits on this to increase the total damage the engi can do, rinse and repeat. though the only realistic way this strategy would work is if the P.D.Q is the wrench unlock.
and only 100 wrenches, lame, at least its random this time and not just given to people who happen to click a link on the site that shows up when half the players are asleep