The problem I have with evaluating draft positions in isolation is it leaves out so many factors. Namely the strength of the draft class and the ability of the amateur scouting making the pick. Plus it doesn't account for the players taken after that position.
Since the #3 pick is being bandied about here, let's look at that in 2013. The 3rd overall pick was Jonathan Drouin. He was billed as an elite, potentially game-breaking talent but he hasn't yet panned out as hoped. So if you look at that pick in isolation, it's easy to say that the 3rd overall doesn't always pan out. However it doesn't account for what might have happened if Tampa had simply decided to go D instead of F. They end up with Seth Jones who was ranked ahead of Drouin on a lot of public lists and is of course an absolute stud. Suddenly it's a stronger case for the 3rd overall being a slot where elite talent is likely to be had. It all comes down to what the list looks like when the team is on the clock. Every team could have a different player ranked at #3 on their board in some years.
Nothing is a certainty, and there will certainly be misses, but the earlier you pick in the draft the better odds you have of finding highly talented players. Then of course you increase your odds as you fall deeper into the draft by acquiring more picks than the ones you're awarded by default.
I mentioned it in another thread, but this amateur scouting staff has shown that their lists don't necessarily align with the public lists and for the most part it's been paying dividends. There have been some major whiffs and the jury is still out on some guys, but there's something to be said about how well they're drafting and how committed they are to sticking to their list.
