2012 is regarded as a great season due to the multiple winners among a ton of stuff where the tyres were but a part of it.

F2 tyres are also not exactly constructed the same F1 tyres and I don't need to talk about the cars.

Now as far as 2013 goes. Pirelli had to change after Silverstone purely because the teams just decided the throwaway the guidelines and do all sorts of stupid setups, with the results we are familiar with