*instant* consequences, for 'good' and 'bad' behaviour. Be consistent about what you will be expecting from him.How can I teach him that he can not do whatever he wants and that I lead him (and not opposite)?
Again, without knowing what the problem is... Perhaps you can tell us where in the world you are(for the sake of internet security, just the general region...)? Then others here might have some suggestions for good 'professionals' if they know the area.How can I improve his balance?
And sad to say, hoof care is something you can't just trust any farrier to do/understand well. Best to put that on the priority list of things you should learn about for yourself. Of course there are some fantastic farriers around, but there are many poor ones, who don't really understand hoof balance & function, so just because you've had the horse trimmed recently & the farrier didn't express concern for anything, doesn't necessarily mean his hooves are in good shape. It is also possible he could be sore/tripping *because* of the trim. While you can't take anything just from pics & info on a forum as anything like a 'diagnosis', you could post some pics of him & his hooves for critique in the health/hoofcare part of the forum if you like. If you want to do that, check out the link in my signature line for what's needed for a 'hoof critique'.