From the horses perspective first; He is only responding to stimuli and through learned behaviour.
I quite agree in the long term sedation does not help, for many reasons but also because a sedated horse is prevented from the ability to learn from the experience and so things will never improve - they can only get worse as you have indicated!
First we have to understand FEAR is the root of this issue, that is how it started, somewhere in his early training. As a result he became fearful, very likely he was then tied shorter, which caused him to feel trapped, he may well have been shouted at, smacked and twitched etc., as his behaviour became more dangerous and people became frightened of injury. No wonder then that he rapidly learnt what would happen to him as soon as the cheerful Farrier appeared. Your horse anticipates what may happen to him - he has a bad memory and has learned to respond violently to try and escape.
This is a problem that can be re-trained, it will mean lots of time and patience and you will need to work closely with both the Vet and the Farrier and quite possibly a trainer who understands and promotes positive reinforcement training methods.
Firstly you need to break this whole thing down into segments and you will need to do this at home with him on your own. Ask your Farrier to show you how he holds the leg and puts it down and make him show you how to create the tapping motion of the hammer. Ditto with the way the Vet approaches the horse.
On a quite day when you have time pick his feet up in the same fashion as the Farrier, do this until he is relaxed, reward him when he does the right thing, either with a neck rub or a small food treat.
Then when he is relaxed tap his foot lightly with the hoof pick or a brush until he is relaxed, REWARD! Do make sure you have a friend with you and wear a hat for safety! Do this over several days.
Hopefully your nice Farrier and Vet will lend you an old apron or Vets smock, now you are beginning to look and smell a little frightening to your horse. Take this stage very slowly - I would just rub the horse (ignore the dreaded feet!) and REWARD, maybe dress like this all the while you carry out your chores, (we are trying to habituate your horse to the sights, sounds, smells and sensations of the Vet and Farrier.) Remember the aim is to get the horse to be relaxed and calm around you. When you are able to approach and your horse is confident rub a leg - REWARD! increase the touches on the leg getting lower and lower, eventually pick up the hoof.
When the horse is relaxed move onto tapping the foot with a hoof pick and brush do this gently do the wall, sole, frog and heel. Rub the foot and REWARD! This must be done many times in a single day over the period of a week or so. Build to the point where you can tap a hammer on the wall of the hoof. When you feel confident with your horse (actually you will be bursting with pride at this point!) ask the Vet or the Farrier to pop by - they must not touch the horse or get too close. Wait for the horse to relax and REWARD, organise for one of them to call again the next day and do the same.
It will depend on the reaction of the horse as to how fast you can take this training, everything must be done at the horses pace, based on his calm and relaxed manner. But you want to build up to where the Vet and Farrier can come and touch and reward the horse and leave. Eventually ask the Farrier to gently tap the feet with the hammer, if the horse is calm he can increase the hammer taps but he must then reward and leave. (If at any time the horse wishes to put the foot to the ground - let him, never fight this urge. Just wait a second or two and try again, remember to REWARD only when he has lifted his foot and is calm)
Eventually your Farrier should be able to build up to taking of the shoes - maybe only one to start with or the fronts or the backs. As long as the whole process is calm and without conflict the horse will learn to associate his hooves, Farriers, and Vets as a positive (food) experience.