You can definitely replace the vac system with an electric/hydraulic actuator, and most likely end up with an excellent braking system.
You need to make sure of a few things, though. A very reliable power supply is necessary, ideally connecting the trailer battery, actuator, and charge line from the vehicle. The charge line must be dimensioned to the specs of the actuator. Make sure you have good brake pads, and fresh brake fluid.
I am using a hydraulic disc braking system in my 1963
Overlander. I am in the middle of installation of the actuator right now. I look forward to powerful brakes on our Colorado trip this summer.