"something is objectively interesting when it violates an expectancy..."
Perhaps, but this definition -- clever though it is -- relies on a degree of subjectivity not terribly far removed from the original definition you cited (e.g., "arousing or holding attention"). Because your definition depends on the reader's expectations, and different readers will have different expectations -- not to mention different weights assigned to those expectations -- then we still can't reach true objectivity in "interesting" content.
"Good writing makes us see something differently. Great writing makes us see everything differently."
Again, this definition is slightly problematic. It assigns too much value to novelty -- which, in turn, depends very heavily on what any given reader might bring to the table. I would suggest we strive for a definition of good writing that is not so heavily dependent on the mindset and other qualities of the reader.
IMO, you were building toward a very reasonable and logical framework in your assessment of novelty + information + insight. (I would add "clarity" to your framework, FWIW). But I think you leapt to a somewhat unsupported conclusion. Not all great writing is profound. To be sure, some of it is (though its profundity depends on the reader's expectations or experience). But there is certainly great writing that shatters no expectations; conversely, there is bad writing that does so. Hitchhiker's Guide to the Galaxy is brilliantly written, but it doesn't exert a profound and life-altering influence on most readers' worldviews. On the flipside, The Secret is horrendously written, but it has had a major and indellibile influence on the lives of many of its readers -- sad though that may be.