They were talking about this on NHL Network on Sirius XM earlier today. Exactly, the big difference is how the other NHL teams learn from their protection processes (i.e. Florida not protecting Marchessault in exchange for cap relief from Reilly Smith). Minnesota gave up both Tuch and Haula. They think teams are going to be much more hesitant about those kinds of pre-arranged deals with Seattle.
Vegas also is the first expansion team in the cap era, and the only expansion team to come in solo (others in the past like Nashville and AtlantaPeg came in alone, but as part of a wave of expansion over several seasons).
The Knights also had, by far, the most beneficial protection rules. In the Nashville-Atlanta-Columbus-Minnesota draft, teams could protect 10 skaters and two goalies (or 15 + 1), which is the closest to last year's 7-3-1 or 4-4-1 formats. In past drafts, 14-15 skaters each was the norm.
Someone probably linked this here last year, but McIndoe had a
great piece last year about the history of expansion drafts. Make sure you've had a couple of cocktails before you start trying to wrap your head around the NHL-WHA merger.