I've had it on a few occasions where there's been different strategies but it's usually only one or two cars that do it. I completely concur that it would make the racing more fun if there were alternative strategies, but there is one fundamental flaw in the idea.
The AI is, or at least it should be, programmed to complete the race in the quickest possible time. With the F1, it's quite close so different strategies would work out to be similar times and they're programmed to mix it up a little due to other factors like car performance, driver ratings and tyre allocations. However, with F2 and there only being one-stop, the driver ratings being similar and the tyres being mandatory, then with this lack of variety, you'd be intentionally programming the AI to not fulfil the race in the quickest possible way which is counter-productive.
For example, if it's calculated that a race would take 51 minutes if they go Soft-Medium and it'll take 51 minutes and 10 seconds to go Medium-Soft, then why would the AI choose the second one when 10 seconds is a long time in racing?
I completely agree that it would make the races more interesting and it should be included though.
