Only problem with your logic is that dragons have been confirmed to pick up giants like small barbie dolls.
In Todd's demo. Never seen it happen yet in a bunch of dragon fights I've watched. Besides, the topic is who is worse to fight for the player, not who would win between a dragon and a giant, so dragons picking up giants is irrelevant.
oh sweet lord, im going to be walk and then a ragdoll from nowhere flies at me a million mph and knocks my guy into the sky and i die....watch it will happen to someone

No first you die. Then you ragdoll. From what I've seen anyway.
Giants are bad ass on every difficulty when you are a low lever. Dragons however start scaled. So by the time you reach level 30 and can beat the [censored] out of a giant. The dragons will be kicking ur ass
I hope so, seeing giants own people with one hit after they killed a dragon was a little disheartening.