He does look better than photos you have posted previously. However he does look very much on the forehand. I'd actually prefer to see him with his head up and his hind legs active and tracking up than with his head down boring down on the reins with a 'pretty' head set.
You really do need to think about getting his hind end active. He may be naughty, but if you wanted to get an ottb then you should be experienced enough to deal with the behaviour issues that come along with it. You want him totally tuned into your aids. Then you can start worrying about his 'frame'. If you put your leg on, you want an immediate reaction every time. If you touch your reins and ask him to slow/halt, again, you want an immediate reaction. If he does not stop and go immediately on cue, go back to basics and get those reactions installed. Ottb's are dangerous when they do not have stop and go.
See how in those photos your foot is at his shoulder? Your leg has absolutely no influence what so ever in that position. There is no way you can ask his hind legs to come up and drive. Really concentrate on getting those legs on or behind the girth even. You will have so much more influence over his hind legs and I can guarantee that you will notice the difference immediately. It doesnt help that you are in a GP/jumping saddle, they put you in a slight chair seat but you should still have your legs back further than that.
From stop and go, you can start doing transitions. MILLIONS of them every single ride. Transitions transitions transitions. Transitions are you best friend. They are a miracle cure! Focus on keeping him forward and active in both the upwards and downwards transitions. Do not think of downward transitions as 'backwards' they are actually very forward movements. Put you leg on through them, and don't allow him to bear down on the reins.
Every time he leans on your hands, throw your reins at him and kick him, make him get up and carry himself. He'll learn that it's easier to use his back legs than to lean on your hands.
I know you don't want your position commented on, but it really does need to be addressed. Don't get your back up please, but I havnt seen one photo in which I've liked your position. You REALLY need to work on it. If you can, get some lessons on the lunge on a quiet school horse. No stirrups and no reins in particular as you appear to rely heavily on your reins for balance. You cannot expect your horse to improve his own balance and carriage, when you are way out of balance and making his job even harder. To train an ottb, you MUST have a very good, solid balanced position. You must give the horse confidence through your own seat, if he feels you off balance, unless he is a balance and rythem machine, he will struggle.