I think the yellow/green/blue board colors that are the defaults of the Diagram Designer, although excellently suited for the main diagram in an article, are are to 'loud' for embedded diagrams in a comment (for which my imagined use case would be mainly to illustrate issues in specific positions).
Let me point out that shortcodes also work on member-submitted pages, which means this feature is not limited to comments. So, I'm not coming at this from the perspective that comments need different defaults than articles do.
Let me point out that shortcodes also work on member-submitted pages, which means this feature is not limited to comments. So, I'm not coming at this from the perspective that comments need different defaults than articles do.