Agreed. Infrigidate is a real outlier, perhaps even the best example of how much procs can change a power's risk versus reward formula.
I'd say Burn has a lot preventing the HC devs from taking a balance pass over it. The proc conundrum is separate though in balance considerations IMO. Then there's potentially instigating a community that has grown accustomed to how it can perform and an actual bug with upfront damage, or multiple pet casting, not quite sure.