I've noticed a lot of discussion about this in the Pirelli 2016 thread so here's a thread just for this type of discussion.
Pirelli changed their structure of their tyres after the 2013 British GP and some fans say that was the turning point towards the racing we see now, I would have to agree.
For me 2011 and 2012 was the best years for F1 in recent time and I would like to see a return to that.