So, I'm still wondering about this.
I've been playing with heat cannons off and on today. They do well against the unprepared, but I don't think they're the problem everyone is making them out to be.
I just came across an elite cmdr who was flying a Python at the Lave CG. I had a FAS with a full loadout of efficient G5 heat weapons. 3 fixed heat cannons on bottom, and a gimbaled heat pulse laser on top.
He had prismatics, and was running multi-cannons with heat-sinks and 3 shield cell banks.
I managed to empty my cannons from nearly full, with most shots hitting. There were several missed shots here and there, but for the most part, I was laying it on heavy. He wasn't running chaff, so the laser spent the majority of it's time on target as well.
I'm hardly the best pilot out there, and I made a few mistakes that cost me, but I was about to run out of ammo when I died.
He lost 2% hull from heat, and kept shields throughout.
On the other hand, when running all PA's on the same FAS, I've routinely heated it up to well over 300% during PvP engagements and survived, having killed my target.
I just don't see what all the fuss is about.
Did I miss the meta?
Are you supposed to kite and use synthesis a few times to slow-roast your targets?
Sometimes people are more afraid of heat damage than other types of damage. The alarms make it seem worse than it is; even if the actual damage is minor.
To be fair though, heat damage is usually worse on modules than it is on hull. Were you able to cause significant module damage to the CMDR's Python?