Reading the heatsink cost thread I had an idea how to reduce the effectiveness of alpha-strikes and yet keep the red line riding as it is now.
The basic idea is, that not all heatsinks need to be active.
If the asset needs to dissipate five points of heat, five heat sinks are active 100%. Or two DHS at 100% and another one at 50%.
Now if the heat increases a lot, by firing a/many weapons, the remaining heatsinks start working, but not in an instant, but with a short delay.
This means that the mech cannot dissipate heatspikes as fast as it can do now.
But if you keep the heat level at a continuous level, the mechanics are similar to the current ones.
I have to admit, that this seems rather complicated to implement, but this would render most mechs unable to deliver alpha strikes with energy weapons only. But chainfiring should be manageable.