First off, any weapons or equipment you can earn through non-transaction economy that is equivalent to the equipment you can purchase through transactions does not fall under the P2W category. Pay to win is clearly defined by the requirement to make money transactions in order to consistently acquire the weapon or equipment that provides clear advantage, however slight, in the fight. Everyone uses the WoT Golden bullet example, which does work, but other P2W exists, such as Lord of Ultima's advisor tool to help manage your cities.
Point is, you can acquire the maximum effectiveness of CoolShot with or without a money transaction, pulling it off of the P2W category.
That said, CoolShot is only going to improve the ability of a select few high-heat mechs, none of those being very useful for competitive gameplay, and most are not even high damage yield. You build a mech that maxes it's speed and firepower, you're still going to have to sacrifice your heat and armor in much greater quantities than what the Coolshot allows in heat forgiveness. An entire team running coolshot with the expectation of being able to take out the other team in a few alphas will find themselves on the losing end of that stick, simply due to the weight restrictions that respectable player tournaments provide.
So no, coolant is a tool that I cannot see being useful to competitive teams, who practice heat management very well, and have much better planning of their mech builds.
Edited by Guido, 21 March 2013 - 01:14 PM.