Such is my disdain for the Nova Cat (and generally all clan equipment unless I'm on the clan team) that I had not piloted a Nova Cat A in 0.3.2 until last night.
Holy, Mother, of God!
I killed an undamaged vulture in ~6 seconds. Alpha Strike (oh noes, not a heat spike, tapped coolant, and before my lasers recharged the damn Nova Cat was down into like 10% heat) I then chain fired the CERLBLs into his CT and with the 5th one he exploded. I don't know any other mech that can do that at 900m.
People are right, though, it's not just the CERLBL. It's the ridiculous heat dissipation of the Nova Cat. 23 Double Heat Sinks is nice, but that does not counter the 60 heat build up in a fraction of a second that the Nova Cat A can generate and laugh off. Let me break it down into Solaris VII terms since that is closer to MWLL than CBT.
The Nova Cat would fire all 5 CERLBLs. This would generate 12x5 heat (x4 for Solaris rules) = 240 heat. The heat sinks would dissipate 46 of that heat, leaving 194 heat. The heat gauge in Solaris is also multiplied by 4 for a total of 120 heat capacity. Guess what, instant shut down. Not only that, but it would take 3 Solaris game turns (2.5 seconds each) for the Nova Cat to cool down to a point where it could restart itself. 1 Turn (2.5 seconds) after shut down 194 - 46 = 148 heat (still above 120). 2 Turns (5 seconds) after shut down 148 - 46 = 102 heat (just barely to a level where you could restart the engine with about a 8.3% chance of doing so.) 3 Turns (7.5 seconds) after shut down 102 - 46 = 56 heat (the mech is finally at the point where it has a solid chance of restarting 91.6% chance.) Otherwise, 4 Turns (10 seconds) and the mech is STILL not fully cooled down 56 -46 = 10 heat (no noticeable problems with the mech, the mech automatically restarts.)
The above is assuming the Nova Cat A is standing still. In my game last night I was jumping and alpha striking mechs and not suffering any real heat issues. I think people are right, the heat system is to blame.