He did so also based on research and at least a value of accuracy, even if his scholarship may have ultimately failed some of the groups represented.
Agreed. I think it's really important not to move the goalposts.
Given what Jim Ward had to work with at the time, he did a good job for what was, ultimately, a piece of late '70s game writing, not academic scholarship that even had a pretense of being accurate. (I mean, it had
nonhuman pantheons as well as clearly fictional ones, such as
Lankhmar.)
At the time having really
any information about most non-Western religions was unusual, to say the least. I bet that, like many other aspects of D&D at the time, there were people who were encouraged to read more based on that book. Lots of us found out about fiction via Appendix N and
Deities and Demigods. It was tough to get then, too, unless you were lucky enough to live in a town that had a good used book store. I would not describe Southwestern Wisconsin of the late '70s/early '80s that way, although the libraries were pretty solid---ironically, I went to the same library as Jim Ward did when I was a kid, although I certainly had no idea.
we might want to be careful before a primarily white produced and designed product responds to these challenges solely by avoiding the project altogether
100%. There's a big difference between the kind of exploitation that existed in media of, say, the late '60s, where groups like Native Americans were portrayed in the ways they appear in Westerns of that era, the numerous examples of Orientalism, blackface, brownface, etc., and being not 100% accurate to current understanding of comparative religion and anthropology (assuming those were even consistently stated and not subject to debate).
I don't know where the line falls, but a retreat to total avoidance is pretty much where the nitpicking will end up if taken to an extreme: Game companies will simply avoid any project that runs a whiff of risk of being accused of cultural appropriation and then slammed on social media.