I have been thinking about the "Burn" mechanic, and while I have not played with the class yet.
I quite like the concept and really drives home the flavor of the class.
What I can see that brings the cost of the burn down is instead of scaling it off the users Hit Dice/Character level that it does currently, instead scale it off the user Con Mod, now to stop this from scaling to a degree greater than it does currently max out the cost equal to the users Hit Dice/Character Level, this means a level 1 character is not shafted by the Burn cost for having like a +4 mod.
Now to offset this you keep the part where you cannot spend more burn than your con mod, meaning you can't "burn" if you have no Con Mod.
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Also while people have been talking about the utility of the class, more will not go amiss (Add my voice to the 4+Int Skill ranks), a few things I want to discuss is the Concentration and maximum burn that can be spent in a round. To me this feels like unneeded book keeping and restriction on the class, like it feels very much like a class that can "nova" very well and I think that too a degree you should allow it.
Another thing that bugs me is that new options become available to the Kineticist at levels 1, 6, 10 and 16. Which to me feels kind of odd and off balance, why not something more linear like 1, 5, 10 & 15?
The other thing is the concentration checks, for a designated blaster whom is designed for combat this feels very odd that the class has no way to address this, and too be honest I don't see what exactly it adds to the class, the AoO you will be provoking (Assuming not using the Kinetic Blade etc.) will be hard enough as it is on the Kineticist. Also the whole spell level of abilities does not help make things easy on the player. I feel you can make the class more interesting through giving it a variety of ways to interact with the battlefield.
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Also a note on the Kinetic blade the "...for telekineticists, you transfer the power of your kinetic blast to any object held in one hand." is very awkward as having something in the off hand means you cant also spend move actions to reduce the burn cost of abilities as it requires to have both hands free, also having the specific restriction for a single "element" like that is just a terrible idea, even if it makes flavor sense, as it any new elements are introduced that should have this restriction for flavor you can't exactly errata it every time, and also it does not really add anything outside of text to the ability.