Sprawling dinosaurs have widely gone out of fashion, so why does it appear that this dinosaurs is sprawled out? Honestly, we can blame it on the angle and the position of the dinosaur. Sauropelta, as a nodosaur, lacked many of he offensive capabilities of other Thyreophorans such as Stegosaurus and Ankylosaurus. The lack of a tail armament would leave two options for a dinosaur like this; use your shoulder spikes or squat down and use your armor; tail scutes have been argued to have been used as scissors as well (see this coming Monday). In this image we have a top down view of a Sauropelta positioning its spikes and balancing its forelimbs in an awkward manner. This could be either to use those spikes as defense or to use them in the only offensive way something like this could be used; in other words this dinosaur is preparing to check an opponent like a hockey player. Which is correct is up for interpretation.
The second option, checking an opponent, would paint a much livelier image of Sauropelta. We would see a more agile dinosaur than we expect for larger armored animals because it would need some agility to be able to lunge at its attackers with anything resembling accuracy. To portray such litheness in a quadrupedal dinosaur requires a little thought on how "bouncy", for lack of a better word, the dinosaur should look. This lean but powerful fore-body portrayed here can help us to look at Sauropelta as a dinosaur ready for action on the front end in a similar manner to how Stegosaurus' pelvic region and tail is all business and looks as though it can pivot and swing with power. This is not a typical thought concerning nodosaurs and their bigger brethren.