We don't need to replace the TSA; it just needs to be run more efficiently without wasting taxes and still keeping safety as a priority.
Replace the TSA agent whose sole job is to repeat the same thing over and over again with a looping video and audio monitor. Heck, a CD player bought at CVS for less than $20 set to auto-repeat does the same job than hiring the TSO for what $20,000/yr per head?
Replace the TSA agent whose responsibility is to cart back the trays over to the landside with say, a conveyor belt or a angled railing that automatically does the same job.
These two would save lots of money just in labor expenses alone.
For international travel, just implement an exit immigration procedure. Lots of countries do this; that's why they have two stamps to put into our passports: one for entry, second for exit. Probably the UK, US, Mexico and Canada are the only four countries that I know of that doesn't have an exit immigration process.