When TaylorMade decided to develop the new Burner 2.0 Irons they really challenged the old "if it is not broken, do not fix it" rule. They succeeded in their quest by incorporating some important engineering and design improvements with the new Burner 2.0 Irons.
Weight distribution was updated. With the short irons weight was repositioned higher to improve ball flight and was centered more to improve clubhead control. With the long irons, weight was moved back in the clubhead for easier launch, and toward the toe and heel for more arguing and stable ball striking.
TaylorMade also incorporated differences in face thickness. The long irons incorporated the thinnest faces. Thicker faces were incorporated progressively through the middle and short irons. Why? Because thinner face thickness accentuates higher COR to promote distance in the long irons and beefier face thickness promotes improved feel in the short irons.
TaylorMade also improved their multi-functional sole design by recessing the heel and toe and beveling the rear to reduce drag and promote more solid ball contact and they revamped their patented Inverted Cone Technology to deliver more predictable distance from club to club and shot to shot, And to enable faster ball speed on off-center hits.
To top all this off TaylorMade has showcased all these design changes with a hot new look. Their new "Burner Black" PVD finish looks great, is more durable and helps resist glare.
All in all the new TaylorMade Burner 2.0 Irons are just as long as the 2009 Burner Irons but they deliver improved playability, more refined feel and sound, and a really hot new look.
I guess the only bad thing about the Burner 2.0 Irons, and the 2009 Burners for that matter, is they incorporated a very "non-traditional" look. So if you are a "purist" these irons may have a bit too much of a "hi-tech" look for you.