If you want to get away from air-assist there are a few options like hydraulic or electric. The problem is the deuce was never designed with those systems in mind. So for the Hydraulic system you will need a dedicated pump and all the hoses and valving. For the electric system you will need an alternator that can handle the power output needed for that little motor.
With the deuces "air-assisted" system you already have everything. Remember all over the road semi-trucks use air brakes. There is nothing bad or old or antiquated by using air pressure to power your brakes. Now if your going to use "Caliper" brakes then you must go to hydraulics. If you have the money I would say "go for it !" . I would love to be able to put all caliper brakes on my deuce. They stop better and are easier to replace the pads versus changing out shoes. There is just no way I can afford them now. The good news is though I don't need to go to caliper brakes to make my deuce stop. It already stops extremely well with the stock system.
"Typical" air brakes, as found on semis and even 5 ton MV, have a much better failsafe than ours. In that they fail on. Granted, your brakes trying to go full-lockup may not be ideal either, but its better than trying to use the engine or traffic to stop your rig.
If I were bobbing my truck, I'd go the same route that Hank went with his deuce. The individual components aren't really that expensive. But sourcing 6 rotors at $100-$150 is a little rougher than 4. Same for the calipers, etc. I haven't looked into the hydroboost master, but I'm sure they can be found in junkyards.
I'm constantly torn between keeping my truck as "cheap and simple" as possible, and making it something that I don't think twice about hopping into and driving to work (my commute is all mountains and tight turns).
For my purposes, I'm going to be completely going through the brake system and upgrading the existing softlines to something better, and making real sure all my hard lines are in order. That and a remote reservoir that I can more easily monitor would make me feel better about the hydraulic side. Eventually the USAF dual circuit system would be a bit of peace of mind.
I would like to add another air tank for emergency braking, with some sort manual valve to bring it online in case of a braking-without-air emergency.