I understand why people are talking about 2012/13 & 2014/15 but the circumstances are totally different. In 2012 we had a great team but Mancini had alienated just about everyone from Khaldoon to the tea lady and had effectively resigned (until he got a new contract). He didn't have the trust of must of his players so they were never going to repeat the performance of the previous season.
Pellegrini inherited a disciplined team that was glad to see the back of Mancini and they responded well to his less abrasive approach. But he failed to build on that double-winning season and the team was already showing the weaknesses that became clear when Pep took over.
This time is a bit like 2012, where we have a very strong squad but we also have a manager who's committed to the club and has the respect of his players. Of course we've still got to go out and win it but with the addition of Mahrez we have the van Persie equivalent that we failed to get in 2012.