From this video:
Good footwork, very solid consistency.
Looks like you depend on your consistency rather then power to win at your level.
Now, there is some element of a debate and subjectivity to this, BUT IMO, as far as the constructive criticism goes:
Now just by looking at the strokes and not where the ball goes, it doesn't seem like anything too beautiful there - not bad, but very mechanical and a bit short.
The way you take your forehand/backhand strokes straight back seems to be a product of a strict begginer/reformation instruction you did not refine much as you grew comfortable with them. It is my opinion that you've just about hit the ceiling of the level of game play that is possible with such strokes (in fact I'm surprised you got this far)
What is supposed to happen is player loosens up that very rigid form to a more loopy form (not always, as there where some examples of pros to the contrary), which pays off with more topspin and pace at expense of perhaps a slightly longer preparation (which should be no problem given your good footwork) for the swing as the racket is taken further back (and most often high up)
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Watch Roddick's forehand and notice how he takes the racket back with both hands, this is a great habbit to have to insure feet placement (which is a bit open for his western grip, but you do that well already) and more shoulder rotation (which is what you need to add more of imo)
http://www.youtube.com/watch?v=DbOal0dK72c
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Similarly with your back hand - take it further back and tuck that racket to your body a little more (by bending left arm in more) and with a little more loop on it.
Also, you point the face of the racket upwards in preparation for the swing, this is your learned way to make up for lack of full swing power with a heavy wrist twist which happens as you change the direction of your racket face to forward. There is a lot more spin to be had here I promise you.
Here is a very exaggerated backhand loop:
http://www.youtube.com/watch?v=QQQfCSI4B78&mode=related&search=
I'm not saying you should loop it THAT much, as you have more strength and don't need it to be that long, but mostly notice how the left hand is bent and close to the body as the forward part of the swing begins.
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Lastly - you make the same mistake (well sorta) as me on the slice - you are using too much shoulder/torso rotation and not enough of your arm and tricep muscle, which results in much less spin and pace being produced.
To fix this I pay attention to have my arm bent in the elbow all the way as I prepare for a slice and concentrate on contracting the tricep as I slice - the difference is day and night - very low deep slice and with pace too.
Again, your legs seem to be doing the right thing here too.
Hopefully this helps (it better! I've taken alot of time to type this up!)