I don't like the marathon in it's current format. Too many going off at once making it a bit of a lottery. A lottery rigged by team tactics.
The field for the medal race should be much shorter, so I'd like to see qualifying heats (2 should do it) followed by quarter-finals, semi-finals and then the final.
To make it fair, the two fastest losers from each of the quarter and semi finals should be laughed at.