Jose Bautista anyone?
No offense, but a guy who (a) strikes out 170+ times a season, (b) just had his first season with more than 2 WAR, and (c) just had his first season with a > 7% BB rate has hardly proven he's "not a flash in the pan" nor is he anywhere near a sure bet to "string together two more good years." Body issues aside, he barely plays 1B better than Fielder, who's one of the worst in the game, and will be two years older heading into his contract (and likely out of the peak of his prime).
But again, Jose Bautista was literally the exact same player, only he walked a lot more and and struck out a lot less, when he signed a 5/$65 million contract with the Blue Jays.