Being drafted before Provorov means nothing. Hanifin's time in Carolina was fairly underwhelming, and he never hit the same production Provorov has. Thats just an extremely poor argument.
Werenski being better than Provorov is debatable at best and laughable at worst. He's a better offensive defenseman maybe, but his defensive game is behind Provorov's, unless were operating under the assumption that this year, and not the previous two, are who we expect Provorov to be moving forward. He plays less TOI in general, almost double as much on the PP, and close to a 1/3 of what provorov does on the PK.
Aaron Ekblaad is the obvious exception to this rule, but i think his contract was kinda poor the moment they signed it - i think we all mostly agree to that, as well. However, if you dont think Provorov's camp with use that as a negotiating point, you're new to contract negotiations.
Let's use Seth Jones as a base, since they're probably the most comparable (young, almost guaranteed to be good/elite #1s). He signed his deal in 2016, when the cap was 73 million. his 5.4M was approximately 7.4% of the cap (for negotiations, your comparables are always in percentages because no one cares about dollar value when the 'available' funds have increased - except Crosby because hes a weirdo). 7.4 % of the cap, projected somewhere between 81 and 85 Million for next year - we'll use 83 as a midrange for this exercise - would be approximately 6.14 Million. I'd say that is just about the floor of what we should expect for Provorov. Keep in mind - that 7.4% of the cap was when Seth Jones had just eclipsed the 30 point mark for the first time - 31 points over two teams - in his contract year. Provorov has put up 30 in both his full seasons, and is pacing for 27 in what were all describing as an awful year for him.
Now, I want to be clear here - im assuming we're tying Provorov down for 8 years, because its the sensible thing to do, imo. Unless we're signing him to a short bridge which would see him remain a RFA at the end of the deal, where we then extend him by 8 years (which carries its own risks, but i digress) a bridge is nonsensical. For added context - Seth Jones' deal takes him straight to UFA. I think we can all agree that the more UFA years you start to buy, the more expensive the contract gets. This has been proven time and time again. On an 8 year deal, we'd be buying 3 UFA years, if my math is correct (and assuming Provorov plays all seasons in between/we dont have a lockout, etc). I dont feel like doing the research on recently signed contracts to gauge the % of escalation RFA to UFA years cost, but for the sake of argument, lets say Provorov wants an extra 10% to commit to this team for those years, and not become a UFA until his age 30/31 season. Seems a little low to me, but again, Im not terribly interested in researching specifics of comparable contracts to prove the point. That alone would necessitate a 6.7M contract (one i'd be happy to pay, mind you) for 8 years.
It isnt an exact science by any means. But if we can lock Provorov down for 6.5 or less for 8 years - i'll be utterly ecstatic.
edit:
@JojoTheWhale didnt see your response until i had started posting this wall of text (sorry), and dont want to clutter the thread with additional posts, but feel free to peruse if you see fit