To select a position for a playmaker you must understand what it means to be a playmaker. So please allow me a little leeway here while I spin my soliloquy about what a playmaker should actually be.
"Welcome back my friends to the show that never ends. We're so glad you could attend - come inside, come inside"
When Michael Irvin first came on the team in his rookie season, he was a crass, over-confident wide receiver. The veteran players had no time for him because they felt like the rookie hadn't paid his dues yet. What they failed to realize was that Michael came from "The U" and his mindset was all about winning. This particuliar Cowboys team was quite the opposite...because they were a lousy team (I mean really bad).
Then this happened:
It was a preseason game against the Raiders and Dallas was having their collective butts handed to them. Irvin was getting really annoyed with his teammates play on the field because they acted as if they really didn't care. So he starts jumping into the faces of his teammates on the sideline to try and get them motivated for the rest of the game. The vets didn't care and they refused to pay him any mind.
Irvin threw his hands up in disgust and was sent back out with the offense for another set of downs. I'm not quite sure who the quaterback was or the safety from the Raiders that hit him, but he was thrown a pass across the middle (and basically hung out to dry by the qb) and got creamed (I mean absolutely leveled) by the safety with a shot "heard 'round the world". You could hear this collective "OOH" from fans and players alike that saw the hit. Mike laid out on the ground for a second and everyone thought for certain he was seriously hurt or got knocked the hell out.
Then out of the clear blue, Michael jumps back up on his feet and starts talking smack to the Raiders defense and then he looks back at his teammates and hollers at them. I have no idea what he said exactly but I bet it went something along the lines with 'that's how you get it done'. The message was sent loud and clear and the feedback was all positive from the players. This rookie had earned his stripes.
That's when the "Playmaker" was born (at least in my eyes anyway).
Now my point is this regarding a playmaker. For starters, he has to be a high profile player. You can't have a playmaker on the offensive line because they're just not going to get enough attention or become the focal point in the gameplan - and really this could be said for the defensive linemen as well (unless they're consistent at getting sacks, tackles for loss or creating nothing less than chaos for opposing QBs) - but perhaps not even that makes them playmakers. Guys like Ware, Martin & White are and were great players (superstars even) but not really playmakers. Honestly I wouldn't even say a player like Deion Sanders is a playmaker because he wasn't the whole enchilada. I mean...sure he was great at coverage and fielding kickoffs (among other things) and he could force an OC to change his gameplan so that the qb didn't throw on his side of the field. But you could certainly run the ball at him, because Neon Deion did not like to tackle.
So really in order for a playmaker to be just that, he needs to be the total package. But, again, it's not just about playing as one. You need to know how to act like you're the playmaker, too - essentially having that type of swagger about you and knowing that you're the heart of the team like Irvin was.
I don't think Miles Austin is our playmaker - yet. He just doesn't put the same fear in the eyes of the DBs like Michael did. Because you knew with Michael, whenever Troy threw him the ball, he was going to kick, scratch, push or whatever it takes to catch it - and then he was going to look at that DB and let him KNOW he caught the ball.
Just like he did that one sunny day in Pasadena, when he played against the Raiders and showed the world what he was truly made of.
That's my opinion anyway.