With the right arrow weight, right broadhead and sensible shot selection, a 40 - 45 pound recurve will do the trick on a deer. That' s what I used before I caught the magnumitis affliction and wound up shooting 80 - 100+ pounds. I' m closing in on being back to 40 - 45 pounds again.
My opinion about these new cams though... There are going to be a lot of people with severe shoulder problems a few years down the road. When you' ve got bad shoulders to start with, you can darn sure feel the strain they put on those joints. The smart choice would be to drop down in weight and accept the performance of your old style bows at 10-20 pounds less draw weight.
Not that anyone' s going to listen to THAT advice.
But, for someone that insists on using ultra light arrows and mechanical heads, then they need that extra poundage. It takes a lot of speed to get the momentum up to where it needs to be with ultra light arrows.