1. I like the idea of the fellowship npc being related to racing, but I don't want that big Galka riding my chocobo. Plus, I'm too attached to him to get rid of him. So, let's have a specific chocobo rider for each character. Give us the ability to choose the race, gender, look, and maybe certain stats for it. Once you've decided on the rider, have a short "interview" with him/her.
Example: Rider says "I believe the harder I kick the chocobo the faster it will run." I don't agree with his/her racing philosophy, so I don't use that rider. A bit extreme, but it made the point.
2. To continue with my npc rider idea, set up a place to speak with him/her at any time. Use this to strategize before the race. Depending on the stats of the rider, different options would be available.
Example: Tell my driver "Pace yourself in the heat", "Save most of [chocobo's name]'s stamina for the last stretch", or "Stay on the outside of turn #2"
3. Chocobos having strengths and weaknesses to different types of weather and terrain is a great idea. However, if my chocobo has an advantage in sand, I won't be racing it anywhere that isn't sand, if I have a choice. So, set up the arena with random types of weather and terrain. This way every chocobo has a chance to take the advantage. This advantage could not be too great though.
Example: If my chocobo is fat and has short legs and is a smoker, sand advantage or not, it wouldn't win a race against a chocobo who was in better physical shape.
4. Gambling. Before each race you have to decide if you want your winnings in gil, or points that can be used for items. This way everybody can get every item available to be won in that manner. However, for the players to get the best items they will have to be great at picking the winners, or have tons of gil to invest.
5. The last one, I promise. Chocobo racing is a great idea, and if done correctly could be a great attraction for new players. Please don't ruin it by making it able to be dominated by high level characters. Just because somebody is a level 75 WHM doesn't mean they are any better at raising a chocobo than anybody else. Whatever level is required to raise and race a chocobo, that level should be at no disadvantage to the higher level players. If there are better chocobo related items in higher level places, that is fine, just make them able to be traded or sold to the rest of us. I don't want to have to level a job to 75 just to be able to stand a chance racing my chocobo.
Thank you for your time
Cheetarrrah (Asura)