I agree with previous posts. It all depends on the individual personality and training of your draft horse that determines if it is a good match for a beginner. My girl is great most of the time and with kids she can be groomed all day you can slide off her butt and stand around behind her and pet her big buns or brush them, pick her feet and flop your body over her back, ride her bareback with a halter, etc. She is a very slow lazy mover and it's almost impossible to get a canter out of her. She is not spooky and we can ride on trails with stray dogs running up barking at us, cars and trucks driving by honking on street, etc. none of this phases her. This is why I got her..because her foundation is pretty safe. However, she is still a bit green under saddle for an 11 yr old because she has only been ridden on trails and driven with cart. It takes about 15 minutes to get her following the rail in arena but she does it and is better each time I ride her. One other thing is she is either super mellow half asleep and great for pony rides or she is has to keep her feet moving (had two trail rides in this mode..not so fun and boy does she know how to canter up a hill on those days)
I think it was because the lead horse was in a hurry always trotting never walking and she felt nervous to keep up or something.
So, for the most part I can handle her okay especially on the ground because she is only 13.3hh and I don't feel intimidated by her size. She doesn't buck or bolt or rear she's got no bad bone in her body and very loving and sweet. I don't know any good horse that is perfect for beginners unless you have strong support by more experienced people around you to help you out. No horse can be handled by a beginner completely. I have a great support system and trainer and more experienced riders around me that help me and a great parelli's instructor who has taught me basics like how to stop a bolting horse and other safety tips and how to train them on the ground, etc.