You might get 1C quality from Duchene once or twice in that seven year deal. Other than that it's not pretty. I know Duchene gave the Preds a discount but he's still going to be an overpaid 2C for most of it.
Zuccarello's cap hit is reasonable but 5 years for him is the ridiculous part. He'll be using a walker in three years at this rate.
I mean, you realize it's Unrestricted Free Agency, right? You're never going to land an impact player that way, without some really ugly consequences down the road somewhere. That's how it works.
As long as Duchene stay focused, i don't see why he can't continue to be that #1b Center type player for the Preds for most of that contract. He's still only 28. Sure, there are gonna be at least a couple years tacked on the end that will be really unfortunate...but that's the price to play in the UFA game.
Same for Zuccarello. Yeah, it's gonna have a couple years at the end where he's a dead weight old man who no longer has the wheels to compete at his size. But it's at least a reasonable cap number and probably only a few years beyond where he'll be worth it.
If we're really talking "best contract" on Free Agent Frenzy day...it's usually the contract that doesn't get signed. But that's not really the spirit of this question. If you want to actually make your team better...you pay the free agency price, and you eat those bad years knowing full well they're going to suck. You're never just going to get a great free asset with no caveats or drawbacks.