It's not so much that it's loosely designed, it's that it's in the public domain, and every manufacturer is free to 'extend' or 'expand' the spec as they feel like doing. Which is why when you call LG support to ask why the CEC isn't working properly, they (ALL manufacturers) say "It's only guaranteed to work if everything connected is our brand."mileage varies between CEC implementations between devices and manufactures. The spec is just to loosely designed.
Yeah, right. Like anyone has all LG (or all any brand).
It was a terrific idea, and if they had kept it 'proprietary' with free licensing, mandating which functions were supported and specifically with which commands, and like with HDMI everyone having to use the same module for maximum cross brand compatibility, it would have worked flawlessly pretty quickly.
But every manufacturer has to dip their wick in it, and so we have the current "it works here but doesn't work there except sometimes when it does if you power things up in just the right order and gut a chicken to read its entrails" debacle.