Raven 3L has an XL 250 in it = 10 heat sinks
A Banshee has an XL 350 in it = 10 heat sinks
Both engines can cool 2 PPCs to a decent extent. But, the Raven benefits from this base heat sink far more than a larger Mech does. Because it is harder to hit - thus better able to dodge damage, and also has the benefit of greater speed because it is a smaller chassis. Now if the larger mech wants to add firepower to its arsenal it has to couple that with additional heat sinks.
All I'm trying to say is that it is easier for a lighter mech to carry its payload with the included heat sinks than it is for an assault mech.
Edit: Since this is feature suggestion, I propose that the larger the engine the cheaper it is to put heat sinks INSIDE it. For instance the XL 350 would have 10 internal, each additional attached TO the engine costs .5 tons. Instead of 1.
Edited by Hyper99, 15 June 2015 - 10:11 AM.