Again that supposes that the Arduino team has full ownership of the bootloader code. I don't think that they do. Optiboot (the one with the issues) was not developed by the Arduino folks, if I remember correctly.
I don't think the mega boards even presently ship with a Optiboot bootloader, it's just a mega specific bootloader? Now that doesn't mean there is not a Optiboot version out there somewhere that has been modified to run on the mega boards or not, and indeed I recall there does exist a 'fixed' bootloader for the mega available somewhere that solves both the !!! problem and handling the WDT correctly, it just hasn't been placed in the arduino IDE distribution nor is being installed in present hardware. At least that is my memory of the existing situation. My opinion is that the 'official Arduino team' has been very lacks (this problem has existed sense the release of the original mega1280 board as best I recall) at implementing a fix for this long standing situation, regardless of who the original developer was and what the best final solution should be.
Lefty