This becomes really annoying, as to drink all of your canteen, instead of just doing the action several times (a bit annoying, a "drink all" option would be nice) you have to keep re-selecting the item and doing the action.

I think this is correct, a typical soda contains what 2-300kcal? It would satisfy your energy requirements for quite a while.

If you only lived off sodas however, I think it would make sense that your character would be less fit and have lower stamina/health.

Yes, as long as you click on exit instead of respawn, you are able to simply log in again even after being shot dead. Will have to verify on latest build though.

Your items might be ruined but there's was nothing preventing me from logging right back in and killing the person who just shot me (I ran away instead, then respawned in the forest). Very exploitable.

Adding to this, it would be nice if the torch had a bright flare around the front when turned on at night, so that you could get somewhat blinded when somebody shined it on you.

A visible beam would also look awesome, especially if a foggy or rainy night: http://www.sentex.net/~mwandel/photo/flashlight-beam.jpg