There is no thread for this at the moment, but looking on the likes of the various websites that list dps etc, would this give the same information and build it up from there?
If so then its just a case of collating the information per website per boss to build up a better % split of damage between magic and physical. Something that would take time but that would be worth it.
Well, at World of Logs, I couldn't find anything related to boss damage throughput, seems like most people consider it a lower priority compared to raid numbers, and since raid numbers/execution turn into a pass/fail scenario, specific boss throughput just gets pushed to the wayside.
Seems it would require a specialized addon to actually track the data, or a specialized log parser. Otherwise, you would have to sit down with a calculator and mess around with the percentages and procs to determine raw damage for almost every ability used.
That was why I was hoping there was already a project under way for this. I don't have the coding knowledge to put something like this together, but would happily donate cycles to testing if it was made.
Edit: the data IS available, I just failed. Going to work on this some when I have the time.