Use AP Style title case in "Change Case > Title Case," leaving prepositions and conjunctions lowerccase
As a former software architect, I've always wondered why "dump capitalization" is the norm throughout editing apps, and has been since Day One -- it's not that hard to do!
The preferred rule should be selectable on a per-document basis so we don't have to keep picking the rule to use (although that could be done, if a specific title needed to be handled differently).
Sam Cantrell commented
Or even, if there was a dropdown menu under Title Case allowing us to select the particular ruleset we wished to use for the text frame.
So you would select your text frame, select Type > Change Case > Title Case > AP Style or Type > Change Case > Title Case > Chicago Style, etc.
Alternatively, you could add a document preference allowing you to set the particular ruleset for the document, but I'd think the first implementation would allow greater flexibility.
I love this idea, but would prefer an implementation that allows us to select the ruleset we want to use when using Title Case (Ex: AP style, Chicago style, etc), similar to how we can select the dictionary we want to use for spell checking.