To each his own. Speaking for myself, a castle shielded in prettied up sheeting would give me no more or less incentive to visit Himeji than a castle shielded in plain white or grey sheeting.

Looking on the bright side ... For people with restricted mobility, the scaffolding offers a unique opportunity to view the castle up close. And for people who are interested in seeing "under the skin" of the castle and observing craftsmen applying traditional carpentry skills, this is also a rare opportunity.

So, I'd say that if you're an Edo period fanatic in a wheelchair, the next few years would be a pretty good time to visit Japan and look at castles. (Visit Matsumoto / Hikone / Matsue for external views of authentic castle buildings - and then go to Himeji for a peek inside and a perspective on how these structures were put together).