A couple of points. Comparisons to the B-2 are not very appropriate as that aircraft has coatings which have to cover a much broader frequency range than either the F-22 or F-35. The comparison to the F-22 is more appropriate and surly LM has had some time to get it much better this time.
Although penetration damage to the composite skin may be a major issue, I don’t see that occurring often enough to be an issue. I also like to see the repair processes to the seals on movable doors, such as the landing gear doors.
Does anyone know how the RN is planning to confirm on the ship that any repairs have been successful from a signature standpoint? It is very difficult to get static signature numbers with the aircraft on the deck and the gear down.
Finally, one of the issues of signature driven aircraft designs is how to dump the system heat overboard. With all access areas sealed little air flows through the structure. Early on the F-35 had heat rejection problems that required more fuel (one of the cooling mediums) be kept on the aircraft than would be required by the operational requirements. That obviously has some operational range implications.