My horse has a speed issue too. The trotting poles will help a lot. What do you mean she doesn't like to trot them? Does she refuse to go over them at all? Or is she just stopping, looking down, and walking over them? Make sure they are good and spaced apart. That way as you go into the poles at the trot she has time to think about the first one before the next one approaches. You will be able to bring them in over time.
Same with cantering over poles, that will bring down her speed some. I find my horse is fastest with he is feeling unbalanced. Canter her in a few circles till you have her together then go down the long side coming to a trot before the next turn and repeat. You could also work on the half halt too. Sometimes I will widen my reins down the long side to slow him then bring my hands back together. This is a variation on the half halt that works pretty well for me.
Keep us updated on what you find works! As I am working on the same thing!