With a few online searches I found
- Nelson's complaint about long book titles and the trend to use colons,
- Kottke's list of reworked titles (then: The Grapes of Wrath, now: California Dreamin': Traveling Cheap in the Middle of an Economic Downturn),
- Rados' rant and descriptive [Punchy Book Title] [COLON] [Incredibly Long Subtitle of What The Book's About, in Case the Reader Doesn't Get Our Pun],
- Rosenthal's request to "kill the colon!", etc.
What's missing is a succinct word describing the technique of using title-colon-subtitle (not just that a book is subtitled, but in an excessive/irritating fashion). "Colon-ized" is the first thing that came to mind, but isn't very good. Is there a better existing word, or one you wish to coin (eg, title-rrhea)?