pro imo means athletes can get a decent living out of their sport. Corporate Sponsors should be able to brand themselves more into the sport. Imagine an red and yellow McD trackteam, just like the footlocker team in the 90s.
I'm glad that NOP and OTC started to have their own uniforms and gears. The SMTC athletes (other than C.Lewis) were also known because of their uniforms. Especially in the distanceraces all Nike or Adidas fields are harmfull for interest (even fans).
Also athletes should race on a regular base and against each other. In some events (mostly field events) it's done, but how often do the top-sprinters race each other, hardly! Even in the Diamond League you don't see match ups. That's what makes track completely differint from the mentioned motocross. They have a series where the topguns meet every race.
Facilities should be good and according to the services offered by other prosports. That means no pro's attending high school meets and tracks without proper stands. One of the best examples is Webb's Mile AR, in stead of Oslo it was done on a small track in rather small (pro) meet (luckily with a camera in the stands).
The secondtier pro-meets should also interest more media outlets to record/broadcast their event or facilitate it self, so that unexpected good results or races can be shown to greater audience.
Get rid of the focus on times and point to winners. In paced marathons, but also sprints, I found myself often saying that a race was disappointing because of the time, rather than the development of the race. You don't see that in cycling. But a top dog marathoner can be a 'loser' if he wins a race without beating a CR or WR.
Teamcompetition certainly helps. Look at last weekends Euro-teams or WC/EC where athletes represent not only themselves but also their country. In the 60/70s you had a lot of teamcompetition, like the USA/USSR meets. Those scored meets are easy to understand. And people often feel more connection to someone who represents a country or club.