I’m dealing with several museums since years as a consultant (or visiting researcher) when it comes to Japanese armor (sometimes also swords and the same) and can totally agree with Ian. Apart from the different views of each restorer/conservator a lot of other things have to be considered and the decision to which degree a piece has to be touched depends on the very piece (condition etc.) and the purpose. For example, when the item is intended for exhibition.
On the other hand, museums are mostly like time capsules. The majority of artifacts remained untouched and unaltered for the last 100-150 years. A great source of information and references. So in view of the abundance of Japanese arms and armor stored away in the magazines, we can be glad if they at least get a proper conservation.
I think the dispute will go on, but there will be probably no right or wrong in the end…