Is it dirty and is this unique among the other raw converters? Even if we had a true and accurate raw histogram on the camera, would we not still need to understand how each converter affected this data?
I would not necessarily call it dirty, but LR does differ in it's approach to Raw conversion compared to other Rawconverters. Besides matters like profiling, it has a very different approach towards the handling of exposure corrections and how that impacts highlight rendering.
There is fortunately a way to create less compressed highlights by pulling considerably (even to -100) back on the highlights slider, but some might consider that a (dirty) trick which is not necessary in other converters. Without that, white clouds and other highlight information looks dull and lifeless compared to other converter defaults.
Of course one can create a default for that, but to adjust the default behavior may also be called a trick.