Im not trying to say its the rookie deal that makes him more valuable. its his play relative to the cost you pay him. it doesnt matter if its a rookie deal, or an 8 year contract. If you are getting similar or better, levels of play from a comparable player, and are paying much, much less, there are very few instances i can think of where the player on the cheaper deal isnt more valuable. The topic i was discussing was value 'today' though, not future value - and the rookie contract does matter for that. It's precisely why no one trades prospects, because good players on short term contracts are much more valuable now and normally, in the future.
For example - Pacioretty's value 'today' is less than it was 6 months ago, because he has less term. However, his value now is probably less than what it will be at the deadline, assuming he has a half decent bounce back season.
For the purpose of this thread, Provorov has more value to me because hes a 21 year old 1D on a team desperate for defense, has 2 top 6 centers already, and he's making 925K a year currently.