I'm a corporate type guy. A business suit wearing, profit maximizing, jargon speaking, "who moved your cheese" type of guy. Here's what I'd do to fix NASCAR:

1. Tweak the dress code. The gaily coloured driver and crew jumpsuits don't cut it. Copy what works for big business in America. Let Brooks Brothers, Armani, or Ermenegildo Zegna come up with a crisply tailored two or three-button flame retardant suit (could put tasteful advertisements on the ties). Maybe declare a race or two to be "casual Friday" type affairs, although I'm personally not too keen on that.
2. Lay-off all of the pit crew except one guy (or gal!). Gross inefficiency here. This fix will save each team at least half a million dollars per year, and make each pit stop way more interesting than they are now.
3. Conduct a driver-satisfaction survey on an annual basis. These guys seem to be pretty unhappy about stuff. Survey them to find out what they like and dislike and then act on it (e.g. do they want a microwave in the lunchroom?, are same-sex marriage benefits important to them?, etc.).
4. Lose "NASCAR" as the brand name. It's old and tired and no longer tests well. I suggest "Amoreg" plus a smiling panda as the logo. Both tested well with wealthy males AND females in the critical 49 to 53 year old Chinese and Hispanic market groupings.

Next: conducting more productive driver meetings; and, hot dogs vs. Hot Pockets - taste or profits?