Oilers need: DEFENCE DEFENCE DEFENCE
It has been our greatest need ever since we lost Chris Pronger (because he's an asshole) following our ill-fated (yet ever so exciting and memorable) 2006 Stanley Cup Finals run and that need has only deepened as the years have gone by. I was quite happy to get rid of Justin Schultz (and would've been thrilled to get a bag of pucks for him) and lo and behold he plays pretty well with his new team in Pittsburgh (and wins a Cup, no less...)... the story of the Oilers roster moves; give them time and time and time to develop their potential, finally get fed up with how bad they are, trade them, and BAM! they're stars wherever they go next (or at least very good players) and sometimes the transition is instantaneous (Matt Greene, Joffrey Lupul, and the worst of all Devan Dubnyk).
I see only one player on the roster as untouchable, and that's Connor McDavid. Everyone else is up for grabs. There are a couple of others I don't want to see go (such as Ryan Nugent-Hopkins, who has been my favourite player the past couple of seasons, and Leon Draisaitl), but given the right package and/or a solid defenceman I'd be happy for team management to pull the trigger and move them out. I really think Jordan Eberle will be gone this offseason, and we may see that move on draft day in Buffalo.
That being said, defencemen are so expensive these days, and in order to acquire/sign one it is going to cost a lot of money/talent, so it'll be tough to build a serviceable defence core on this team in just one offseason. And, frankly, the depth of upcoming free agent defencemen is pretty thin... There are a number of good RFAs we could target, such as Torey Krug, Tyson Barrie, Sami Vatanen, Seth Jones, Rasmus Ristolainen, Hampus Lindholm, et cetera, but they're likely to be re-signed by their respective teams or those teams will match any offer we or other teams make, so it'd really be wiser to look for a trade or a UFA. But the UFA market is really thin; the best available guys are going to be old and expensive (Brian Campbell, Alex Goligoski, Keith Yandle, et cetera).
It has been extremely frustrating being an Oilers fan the past ten years, but at least a bunch of clowns aren't running the show anymore (Kevin Lowe, good riddance), so we'll see how this offseason goes...