I do think you're higher on him than me, and I doubt we'll be able to agree on that, based on past conversations. A lot of his 2013 production came from 2 games, and 3 busted plays in particular. You've seen the stats, so I won't go into them. I'm not telling you how to weigh that data, but I personally do give it some value; especially when it matches what I see when I watch him play. He's a very solid NFL back; not a Shady-level player.
As for him having one of the best rookie seasons ever - there's a guy in Washington who did the same, yet has never been treated as a top 3 dynasty back. And as for him having the best burst, power, elusiveness ratio - I don't think he's close to Adrian Peterson.
Morris and Martin are similar until you consider the receiving yards. Morris caught 11 passes for 77 yards last season while Martin caught 49 passes for 472 yards. Last season in PPR Martin averaged 19.6 ppg compared to 16.1 for Morris. That's the beginning and end of the debate with those two. If you want to diminish Martin's achievements you can say that he only got those yards because they fed him targets, but given how effective he was with his receptions it seems pretty clear that those opportunities were based on merit more than anything else. He was no more a product of his usage than Brandon Marshall, AJ Green, or Jimmy Graham. Good players command chances. Coaches want to get the ball to their best playmakers.
Again, it's a chicken and egg thing. If you want to give the player the minimum amount of credit, you can say that he only excels because of his opportunities. You can also say that someone like Morris would be just as good as Martin in space if given the chances. I don't really buy that. I think most players tend to get approximately the opportunities that they deserve. And that makes sense because football is a competitive and efficient enterprise where coaches are looking to make the most out of their assets. You wouldn't expect them to feed 200 targets to a horrible WR just like you wouldn't expect them to never throw the ball to a RB who would otherwise be a dominant force in the passing game.
Suggesting that Martin was in some way a product of the usage in Tampa is IMO a thinly-veiled and probably unconscious attempt to cling to an outdated evaluation of his talent. The idea that, "I didn't think he was that good, but he's playing extremely well, so it's probably the usage more than it's me being wrong." I think we're all guilty of that type of thought process at times. There are times when it might have some truth to it and some times when it's pure ego protection denial. Obviously with Martin I think he's a pretty legit player. Maybe not top 2-3 overall RB in the NFL legit, but plenty talented to be a Forte/Lynch (similarly versatile backs who have never at any point been considered ELITE in the same sense as a Peterson/Tomlinson).
As far as the "McCoy is just more talented" stuff, I think it goes back to what I said about people having a preference for smaller, flashier backs. People think of a guy like Spiller, Charles, or McCoy as being more talented than a guy like Gore, Martin, or Lynch because they have a flashier playing style. Smaller players rely more on quickness and speed, and those are probably the main things that catch the casual fan's eye. So almost inevitably any time you have a debate between a guy like McCoy and a guy like Martin, it is always going to be the consensus that the flashier player is more talented.
IMO power, strength, and the ability to handle a high workload are also components of talent and that's where Martin has an edge over those smaller guys. He might not have the pure speed or cutting ability that they have, but at the same time they're never going to have his stiff arm or balance after contact. You can even extend that to inferior power backs like Greene, BJGE, Moreno, and Ridley. The things that they're good at (strength, power, balance, volume) are very boring. Thus those players tend to get slagged as pure mediocrities a lot more than they probably should be by the FF public, who get more geeked about a 200 pound back carrying it 12 times for 70 yards than a plodder lugging it 24 times for 80 yards.
The reason why I like to point out the 20+ yard run stat is because it flies in the face of the perception of Martin as some kind of undynamic modest talent. The guy broke A LOT of big plays last year. Whereas Spiller or Chris Johnson might get their long runs with pure speed and explosiveness, Martin might achieve the same net result with his overall combination of power, agility, initial quickness, and vision. The "how" of it doesn't really matter. As long as he keeps stacking up big plays, you can't say he's not dynamic.