In my experience, you rarely see AI wrecks unless the player is involved, and always follow the same racing line. I really wish the individual drivers had their real-life characteristics somehow included in the AI model.
I played intermediate as Marussia/Virgin in previous games and had no problems with winning or finishing in the top 10. I didn't really like that, and wanted more challenge and realism. In F1 2013, I am racing for Caterham on intermediate level and after six races, I have three races scoring points (8th, 9th,10th) and other finishes in the mid to low teens. Highest qualifying place was 15th. The race pace, however, is a huge problem. Even on intermediate, my Caterham is usually 3 seconds a lap slower than the AI, meaning within 20 laps I am usually lapped. The only way to get into the points and keep it is to fight for my places in the first few laps, then hold my place as best I can via blocking. Catching up to someone ahead of me is absolutely impossible unless they have pitted or there is a safety car involved.
I am curious if the AI is affected by parc ferme? I am currently racing Monaco, and FP was sunny, qualifying was predicted rain but ended up with no rain. Rain was expected for the race, so I set my car up for a wet race. Not sure if the AI stayed with a dry setup or wet.... there has indeed been rain in the race and I still have seen no advantage over the AI despite having the best setup for a wet race as possible.