There are a few differences:
1. I don't think we really know how long class D amps will last, how they will most likely fail, or whether they can be maintained in the same sense as a conventional amp. They could last longer.
2. Class D amps use far more complex designs. Many of the amplifier boards are built as modules and used by multiple amp makers. That's why a class D amp will often be identified as a Nilai, NCORE, Purifi, PASCAL, etc. Some (all?) of these companies also build and sell compatible power supply boards. Add a case, power switch, input buffer. wires & connectors, and you're done! I don't think all class D amps are built this way, though.
3. The more recent introduction of GAN FETs has made for another family of class D amps. I don't know if these are also mostly being based on modular sub-assemblies; what makes them distinct is the use of a specific kind of transistor.
None of these are necessarily negatives, just things that occurred to me recently. Hopefully, @atmasphere will drop by and fill in the blanks (please?)