I recently stumbled upon this very interesting piece by Mark Parnell on Medium about consistency in design.
In short, consistency is not and cannot be the sole criterion of good design. Building a consistent design system is important, but over-zealous quests for consistency can be at the expense of other aspects of design.
I really like the Google icon redesign example of a case where consistency is actually counter-productive:

Funny ‘cause it’s true.
What are your thoughts on this topic?