I've long though the World Championships and the Olympics could be improved by eliminating some of the rounds. An example is the men's 1500.
In Round 1 today, there were 3 heats with 41 competitors. Only 17 of the 41 were eliminated for the semis. There will be 2 semis of 12 each. Half of those will be eliminated for the final.
Why not just eliminate the semifinals and go straight from the heats to the finals? Perhaps top 3 in each heat plus the next 3 fastest. I don't think there's much revenue for the extra round. The first round is in the morning session that is lightly attended. A semifinal where you had to finish top 3 for an auto qualifier would be a much better race than with the top 5 automatically making it.