Final note: let's understand the mindset behind the pick for a moment. Belichick clearly felt that Dowling had far more talent than his draft position indicated. Given what little we saw of him when he was actually healthy, I can see where that impression came from.
It was a gamble, absolutely. But to call it the 'worst pick of the Belichick' era because it didn't work is just a fundamentally, deeply stupid to say.
To borrow an analogy from poker, blackjack, market speculation, drafting NFL players, or anything else: the right move is the right move, even if the results don't always show it.
If you have a 13, and the dealer is showing a 10, you hit. You always hit, every time, without exception. If it just so happens that you get face card and bust, then so be it. The fact that you busted doesn't mean that you made the wrong move. It means that the right move happened to have a bad outcome this time around.
Personally, I'm inclined to feel this way about the Dowling pick. Picking players who have red flags re: health, legal status, etc. is a fantastic way to get a player who is far more talented than his draft position would indicate. Sure, we've ended up with some lemons like Tate and Dowling, but it's also how the Pats got Gronk, Chandler Jones, Dennard, Cannon, and I'm sure some other guys who I'm forgetting. Someone like Gronk is basically equivalent to hitting on 13 and getting an 8. All of the idiots around you will think you're a genius for doing it, but in reality you're no smarter than the guy who busted. You both made the right move.
If you're going to argue that Dowling was a terrible pick, then you have to argue that using information that was available at the time. Argue that his upside wasn't nearly high enough to justify the injury risk, for example. Or argue that his injury track record was too alarming for him to be worth the pick (be aware: if you're arguing this, then you're implicitly arguing that Gronk was also a bad pick, since his injury history was worse than Dowling's).
Whatever you do, don't say "it was a bad call because, in hindsight, it didn't work out". Revisionist history is for stupid people.