I'm really going to try to develop his hind end and makesure to work on getting him using that rather than falling on his front. I'll try and get some videos up and see if any of you see anything I could be doing wrong as well.
If he does the speedy trot before the canter, have you tried spanking him to make it crisper? I'm having to do that with my little pleasure guy right now. Also, lots of canter to walk to canter to trot to canter to walk to canter to walk to canter ect transitions. It give my guy the benefit of anticipation so he's ready for the departure when I ask. He's getting much better.
I'm an English rider but I would not allow him to canter from a fast trot. If you ask him to canter or lope and he goes into a speedy trot, try going back to walk. Then go into a very collected trot, ask for a canter in a corner, turn, circle, if he goes praise him, if he doesnt go back to walk and start over. If he's in an extended trot he wont have the impulsion to go into a nice canter.
How that would work in western I have no idea....