I'd like to see the Monk weapon "group" expanded a little bit, especially since it seems like they have no way to get crit specializations on them from their class anyway. Things that aren't monk weapons but it makes sense to have them be monk weapons include:
Gauntlets, spiked gauntlets (a punch is a punch, right?)
Sickles, staffs (kama and bo-staff are monk, but not their basic variants?)
Daggers (sai and dagger are related enough. why not?)
Blowgun (why not, because ninjas. nobody gonna use em anyway)
Not all of those need to make it in, but at least sickles and staves please, it doesn't make sense that I can be good at using a long stick but not a short stick. :)
Additionally, it wouldn't be amiss to give them trained in simple weapons to start with. Otherwise a monk starts with no ranged options unless they burn a feat.