After two seasons on the job, Edmonton Oilers general manager Stan Bowman needed a win this summer.Judging by the chatter in this city, it sounds like most would agree he scored a few. Adding a Stanley Cup-winning goalie in Frederik Andersen and late-blooming defenceman Ryan Shea were widely lauded moves.Getting out from under Darnell Nurse’s $9.25 million cap hit was something bordering on the miraculous. With precious time wasting in the Connor McDavid era, the deal was all but guaranteed to be a burden on the roster for the next four years. By shipping it out with zero salary retention, Bowman made out like a bandit.This offseason appears to be a step in the right direction for the Oilers. But the work is incomplete. Bowman will ultimately be judged by the yet-to-be-made moves that this offseason’s deck clearing allowed for. That $4.725 million in cap space, according to PuckPedia, will likely define this season’s outcome.But that doesn’t mean we can’t be critical of the Oilers’ current roster heading into the season. Because the jury is still out on whether this team has improved at all over the version that bowed out in six games to the Anaheim Ducks this spring.Aside from the two aforementioned additions, depth defenceman Shakir Mukhamadullin and winger Mathieu Joseph are the only other incoming players who could be considered NHL quality. Up front, the forward group lost Jack Roslovic without replacing his middle-six utility.So, let’s assess whether this Oilers roster has really seen any notable improvement, using Dom Luszczyszyn’s Net Rating model.Big picture: A minus-1.5 Net RatingAt first glance, this might be discouraging. Following up a regressive season with a regressive offseason isn’t ideal, particularly when arguably no NHL team faces more pressure to win immediately than Edmonton.However, that number undersells a few things, like just how good the roster already was. The Net Rating model favourably viewed the Oilers as one of the league’s premier teams entering the offseason, and it remains bullish, spitting out a league-best offensive mark and the fourth-best overall rating.The other factor that could go unnoticed is coaching. Mike Babcock is projected to have the most outsized impact of any new coach this season, estimated at between eight and 10 goals. While that influence is partly informed by Babcock’s first year with the Toronto Maple Leafs a decade ago, in which he had a large impact, Luszczyszyn’s methodology is far more robust. His model seeks to isolate a coach’s true impact by analyzing how every returning player’s average rating improves during the first year of every coach.