hurr chaaaaarge, alpha strike, flush coolant, alpha strike, flush coolant hurr derp
Heat is currently pretty much pointless. It's meant to be a brutal method to keep the rain of lasers, PPCs and missiles at an acceptable level. Alpha strikes should be an unusual exception, not the norm.
For instance, firing 2 large lasers puts your heat in the red. No problem, wait 5 seconds and it's fine again. Some of the heatsink-heavier designs don't even need the shutdown override most of the time. By the time the shutdown timer runs out, you're below the shutdown threshold again. Whee!
Or put some of the free coolant on it. Who cares about heat anyway? Coolant is abundant and by the time you run out, chances are you're on your way to the repair bay anyway.
This doesn't make sense to me, all that coolant in your mech should make for a larger heat capacity. That is, you can create more heat until the temperature goes critical, but you dissipate slower aswell. An overheated mech should take a while (10 to 20 secs?) to cool down.
Vehicles shouldn't have to deal with heat to the degree that mechs do. This was one of the defining features of tanks in CBT and may also help distinguish them from mechs more than them being mechs without legs that can't turn in MWLL.
Also, there are no repercussion for overheating mechs. Sure, when you reach the critical point, armor plating starts dropping from your mech (lol!) but below that, whatever. Skin me for comparing this to BTU and CBT, but a mech that runs hot has a lot of problems to deal with. The reactor reduces its power output in order to keep the mech from going kablam, causing a reduction in running speed. Targeting systems go haywire (MW3 had a nice effect for this), ammo may start cooking off resulting in devastating ammo explosions. The MechWarrior starts sweating like crazy, vision gets blurry, reaction times are slower, hell, he may even pass out.
All of this is not represented in MWLL. (I know that the new beta is just around the corner, but due to the secrecy behind it, that doesn't stop me from discussing these things

)
So here's a few suggestions I'd like to see in MWLL:
- Increase heat capacity by a great amount (this will need some testing as to not allow mechs to swallow a few alpha strikes with their heat capacity)
- Make coolant one-shot. It can still help you in a really tight situation or when you fall into lava, but stops being an alpha-strike generator
- For those that can't live without coolant, allow them to buy additional coolant pods for their free tons. These should be externally mounted and explode violently when struck with enough damage

- A louder alarm bell so you don't miss the shutdown warning in the middle of a fight

- Implement effects when at high heat. Scrambling HUD, blurry vision, slower running speed and maybe ammo-explosions
This way, a Mechwarrior can choose whether he wants to fire a lot of weapons and overheat fast, or fire few and keep the heat in check. This allows people to behave differently depending on the situation or their style.