That's not my experience. Actually, it felt alot freer than it was in 1.1
I was out trading and was able to exit the station, boost, boost boost, jump without having to wait for my ship to cool down. It never reached 100% and never took any damage. - before, I'd have got warnings and maybe some damage if I'd done that.
Later on, I switched to my Asp, went out jumped scooped - letting the temp get up to the 90's and again, no damage taken. I went mining, and did some combat too with no damage from heat at all. The only damage that I took was from a brief period when my shields were taken out. That was about 300 credits worth, so wasn't really a big deal.
As for the heat 100% now means, don't go above this, which is more intuitive.