Letting a body burn, rot or being mummified isn't any more respectful in my eyes.

I'm not too concerned about the transmission of diseases after composting (the presence of pathogens in the resulting compost will have to be assessed, but I don't expect them to fare well in soil. Prions may be harder to get rid of...).

My main concern would be about the plastics and metals from prosthesis and tooth fillings that would end up in there...