I watched this kid in 2 dev camps and in a couple of Caps exhibition games in September. He was paired with Brouwer and the Walker kid from Australia in this year's Caps training camp and they were very effective together. The fact that Stephenson made it to the last week of training camp indicates that the organization was impressed. Then he followed up with a huge season for Regina, which was not a very good team his first few years when he was hurt a lot, and he led them to the playoffs this year.
He got the max entry-level deal, so that also says something. I'm not sure what, but something.
He's not very big but he's got a good base (much better than Perrault), very quick and very fast. Excellent vision, made Brouwer and Walker look good in those preseason games. Very responsible defensively. Left-handed shot, so along with Kuznetsov, he helps to balance out the excessively right-handed organization.
I'd say he was similar to Eakin but with a stronger base and body, so he's harder to knock off the puck at this age, and solid in all 3 zones. I think his current tool kit gives him 2nd line potential, but you never know how these kids are going to develop.