A blaster bolt can be deflected by a lightsaber.
Assuming a blaster bolt works similarly to a lightsaber, it also cannot penetrate certain materials such as Mandalorian Iron or Cortosis.
A non-direct hit from a blaster bolt is usually not fatal, as evidenced by Leia getting hit and it's 'just a scratch'.
When hit in a non-vital part of the body, say, an arm for instance will hurt, however the wound will immediately cauterize and does not cause bleeding, so a wounded limb is therefore not fatal.
Blaster bolts are easily discharged by shields. Apparently these shields are easy to make since every Droideka has it's own, not to mention every Bounty Hunter running around with one.
Now, considering all this. Why the **** doesn't anyone use good old gunpowder.
they do use them. Mainly primitive races and Jedi Hunters. But yeah Blasters are inconsistent as far as damage goes and they never seem to be that accurate. I just assumed because they are incredibly cheap to make it's easier giving your military of several million people a weapon that is cheap and never needs ammo.