Firstly, I believe you should concentrate on making him want to come to you first & foremost. If your horse doesn't want to be with you in the first place, this tends to get in the way of other issues. Make yourself the better option, rather than just the better of 2 evils, by going there just to hang out, give him a scratch, treats, grooming - nice stuff. Hold off or greatly reduce the stuff you know he dislikes for the moment, until he's come to expect Good Things from you too. Then just don't forget to do Good Stuff with him regularly too.
He'll run away, etc. I don't chase after him because I know that will only make him keep going. When he walks away, I'll say "no" in a firm voice and either walk away or just stand where I am....wait till he stops and go to approach him again. But it's hard because he doesn't want to be caught when there's another horse with him. Now, by himself, he's fine...he'll stay and let me catch him....but it's almost as if he's showing off to his new friend lol.
After you've established the foundation of a better relationship, then you can strengthen & direct it with negative reinforcement - that is, the removal of something unpleasant - pressure. I think doing just about the opposite of what you are doing is a good start :roll:
Naturally, putting unpleasant pressure on anyone will make them want to find ways to escape it. Your horse is escaping the pressure of your approach by walking away. When he does, at present, you're reinforcing his behaviour by taking the pressure off - quit following or walking away. Each time you repeat this, you're making the behaviour stronger! So, it's had a bit of 'training' already & it may take a bit of patience to 'untrain'.
I would start this phase in a small area first, for your convenience(unless you want to get fit!
), and have the responses reliable & well established before trying it in a larger area & with obstacles such as other horses.
Now your horse should be reasonably reliable about coming to you anyway now, but any time he walks away, follow him passively. Meaning follow, but without strong focus, without much energy in your bodylanguage. So long as your horse is leaving you, keep that bit of pressure on. Make the 'wrong' thing difficult.
The instant he even thinks about slowing or stopping - even if it's just cocking his ear at you or lowering his head to begin with, turn & walk away from him. Make the 'right' thing easy. With repetition you can gradually ask for more, until he learns that what works(to remove the pressure) is to stop & face you. You can also begin to get less dramatic about the removal of pressure & just quit following.
After this behaviour is well established, I then 'refine' it further by asking the horse to come to me. I will repeat these lessons in a variety of places, including the paddock to help him begin to generallise that walking away from you anywhere, in any situation leads to Bad Stuff.
2) If the horse was gelded late, or otherwise has rather dominant, stallionish behaviour, this is often strongly ingrained, as it's such an imperative instinct. It may be difficult to get him out of this behaviour in the paddock, but I would be inclined to run him with a group of mares & let them teach him some manners!
You also need to earn enough respect from him to prevent him doing this when ridden or handled! It's not just him that could be kicked & the owner of the other horse might get in the way too. I would suggest practicing your negative reinforcement skills in many ways, not just for catching, to teach him to yield well.
I would also use one rein to bend the horse, as an emergency control measure. While the only ultimate use for this is as an emergency brake, it does need to be well taught & established, so that it is a yield(soft response with understanding) not a forced thing.
Firstly, improving your relationship, teaching him you're trustworthy & will consider his feelings & ensure safety will help. As part of this, you can do lots of desensitisation to scary things, using 'approach & retreat' to avoid confronting him with his fears and keep it low key. Do lots of practice in a controlled environment (meaning you can control the distance & intensity of the scary). That way, you can also find a level to start at that he won't run you over, and teach him to respect your space & teach him if he feels the need, run round you, not over you. On the ground and then ridden. Teach him that he just needs to focus on you & you'll keep him safe. Then when you are out & about, follow the same routine.
It's not so much security of the bit IMO but he has learned that he needs to comply with a bit or Bad Stuff happens. Without it, he's not so sure you should tell him what to do. I'm definitely all for bitless riding - I think bits are *generally*(never say never) one of the problems in any equation between a horse & human.
However, I think you need to work on a fair bit before it will be safe for you to ride bridleless. My approach would be to establish everything on the ground first, then riding with a halter on a loose rein(you want him to learn to respond to your seat & legs, rather than just reins) in a small enclosure at slow speed, before gradually working up to refined control at a canter, then repeating it in larger areas & the open. You might choose to continue riding a little with a bit while you work on everything else first.