A lot lower ration spawn, but higher rate of restore (assuming you can have the full 5-seconds of it). Have the Hunger effect turn into a curve. Make it tick a lot slower to start out, and move into gradually up to its pace on live +20% or so, with eating resetting the rate of decay.
Still won't get you to survive bullets, but I think that change would probably help a fair deal.
Edit: Also, putting the bots into the sky a bit, so they hover above the players' heads rather than be sources of collision would be nice.