Every player you mention, I went Hmm in agreement with you. Dang that's a lot of bad deals out there.
Thing to keep in mind is expectations. Most of those deals are more than 3 years old at this point. So when teams made those deals they were using data from likely 3+ years even prior to that to adjust their thinking. A lot of the reason deals become bad is players just finally get old. And in the case of the time frame from those deals you had a lot of players who likely were over performing their age projection because of hgh/steroids. That in turn is a vicious cycle itself because once you have a guy like that you're a bit pot committed already. So, you are more likely to press in FA for more because rebuilding with a $100+ mil contract on the books isn't fun. That in essence is the tigers right now and to some extent was the Angels with Hamilton/Pujols.
As all this pertains to Heyward, I've said it before and I'll say it again. The 5/$106 he has left after this year really isn't that big of a deal. Cain literally just got 5/$80 and he's 4 years older than Heyward is. Cain's best seasons were age 29(6.5 fWAR), age 28(4.8 fWAR), age 31(4.1 fWAR), age 27(2.7 fWAR) and age 30(2.5 fWAR). Heyward will be 28 this year. So in a typical age curve you'd expect the next 4 or so years to be his most productive. Maybe he's Andruw Jones who just fell off a cliff after age 29. But Jones is literally the only guy I can think of in the past 25 years who was healthy and was on a potential HoF type career to just utterly lose it before they turn 30.
Regardless, I'll take the over on Heyward having the 11-14 fWAR his remaining 5 years after the opt out expect. Frankly if he has 1 or 2 years at 4-5 fWAR which isn't entirely implausible given he's already done it in the past, he would totally right the way the contract looks. An 8/$186 mil contract is an expectation of roughly 20-23 wins of which he's got 2.4 in the first 2 years. Him getting to 3 wins a year for the remainder of the deal isn't that difficult especially if he has a couple 4-5 win seasons. Fangraphs was down on his defense last year for some reason. I'm not entirely sure why given he looked as good as ever there and won a gold glove. But for the sake of argument if you took his 2016 defense and pair it with his 2017 offense he would have been worth 2.3 fWAR. Another way to look at that 3 win mark is 2013 where he hit .254/.349/.427 with his typically great defense and was worth 3.4 fWAR. Only difference between that and the .259/.326/.389 he hit last year is a 1.5% walk rate decline and a marginal increase in his slugging. You're talking about a 3% shift in his soft/hard hit rates to get that slugging. He was basically at a 2% change from 2016 to 2017.
So, it's not like it's impossible for Heyward to live up to his deal. If you want to bet against him go for it. But he strikes me as a case of coaching just messing him up by making him change in a similar way to how the O's screwed up Arrieta. Obviously Heyward's swing had issues in Atlanta and St. Louis/Cubs thought they could get more out of him by "fixing" things. Sometimes guys just gotta be what they are.
