I was asking if it was possible WITHOUT sneaking.
No you don't, you said you killed a dragon using Sneak. But after that you just asked if it's possible to "if the right items and gear make that possible in a 1v1 fight".
You never implied or actually asked: "Is it possible to kill a Dragon on 1 hit without using Sneak"?
But it is possible to kill a Dragon in one hit, you just got to be lucky, and by that I mean very very very lucky.