Even if the thermal cooling doesn't give Canon sensors as high a DR as SoNikon Exmor, thermal cooling combined with two additional bits should give them better overall DR (assuming Canon doesn't jack up ISO 100 read noise to 100e-!!! :''''( ).
Um, what's this thermal cooling supposed to be exactly? A fan on the side of the camera? Heat dissipation through a part of the camera that has a "never touch here" sticker on it?
No details yet. It could just be a heat pipe cooler, which is an efficient way to passively draw heat away from the sensor and possibly to the shell. If heat is drawn away to multiple external dissipation points, none of them should be too hot to touch. Another option would be peltier cooling. A Peltier is a thermoelectric cooling device (TEC) that uses P & N type silicon nodes in an array sandwiched between ceramic plates to draw heat from one side of the peltier to the other. They are extremely powerful coolers in very small packages (say, exactly the size of the sensor die?). They generate their own heat, but the thermal differential from the hot side to the cold side can be on the order of tens to even hundreds of degrees. Even a moderately powerful peltier in a camera could cool the sensor to sub-freezing temperatures. Combined with an advanced heat pipe sink and maybe some fans, and you could dissipate a LOT of heat from a sensor, and nearly eliminate electronic noise if you cool it enough.
And Peltier cooling would require lack of LCD in the rear. Reasonable power and termosensors management could make such a solution really a breakthrough with relative small costs. The main problem here I see is a heat dissipation - some kind of quiet radiators or noisy fans would be neccessery and radiators could burn photographers hands. Radiator would heat other camera regions and most probably could cause weight increase. Anyway, it's really worth of consideration, if the radiator could have a good mount to the tripod plate, which could help dissipate the heat. There are landscape and studio shooters, who would be more than happy having much higher image quality, without even noticing, that the tripod is 5 degrees warmer.