I've been trying to build some fast planes in 1.2 (a lot of my ksp craft are high speed planes of some type, and very few of them ever go to space), and testing them at low and high altitude to see how much altitude affects their performance. My assumption was that, due to the thicker atmosphere, planes at lower altitude would experience more drag and atmospheric heating. However, I didn't notice as much difference between the performance at low and high altitude as I expected (high altitude heating was if anything higher than at low altitude and drag only seemed to be noticeably higher at low altitude with a fairly flat nose). The heating difference might be due to residual heat from lower altitude flight though and I might just not have gone fast enough to encounter higher drag with the pointy version at low altitude.
Is this normal and I'm just an idiot, or is this a bug, or something else? My guess is that it's normal behaviour, just not as pronounced as I was expecting/have encountered in earlier versions of KSP (not that I've done much low-altitude high-speed flight before)
(I don't now anything much about aerodynamics and atmospheric heating except what I've learned from far too many hours building aircraft in KSP (with and without FAR) and a little forum-browsing)
P.S. The testing wasn't especially scientific as I have only tested 2 variants of 1 craft (with blunt and pointy noses - NCS with 0.625m nosecone or 0.625m ablator-free heatshield on the end)
http://imgur.com/a/lkmQr - various pictures with varying degrees of helpfulness.
EDIT: The pointed nose seems to be able to achieve about 1600 m/s at sea level, 10km and 20km, with the heating being slightly lower at 20km. The blunt nose can get to 1175 m/s at sea level and 1600 at 20km, without much heating showing up at all.