Creating a situation where the best in the world compete against each other with regularity would do more for the excitement of the sport than any of the gimmicks mentioned. In most other sports, fans get to see big time match ups multiple times per year. In track, we pretty much just have the WC and OG. Any other time a couple of good guys race against each other, we feel lucky to get to see an actual exciting race. We shouldn't feel lucky to get to watch the best compete against each other on rare occasions. We should expect it to happen all the time.
I would look to tennis for a model. Tennis has four events every year that bring the best players in the world together. No top player who is healthy would even consider skipping a major.
If tennis worked like track, Federer and Djokovic would have only played each other two or three times in the last 4 years, and they both would have spent the rest of their time beating up on no-name players at small time tournaments. Because the majors exist, we know that we'll see guys like Fed, Djokovic, Murray, and Nadal playing against each other a whole lot.
Track needs a handful of meets that are actually important. Not just DL meets, but meets that no professional runner would skip if invited. We should have the dozen best 1500 meter guys stepping on the track together in a final for meaningful prize money four times per year.