Exactly, Pandoc chooses robustness over buggy half baked conversion. Swiss Army Knife is no good when you need to a debone a Tuna. Every tool on a Swiss Army Knife is sub-optimal. It's a terrible popular analogy in general.
I don't know much about tuna, but I once cleaned a bass with my swiss army knife.
Anyway, I don't really expect Pandoc to do everything, but when you have both Calibre and Pandoc in your toolbox, it sure feels like you could manage close to anything.