Agreed, for managers brought in the PL is ridicously strong compared to when Ferguson/Mourinho/Wenger were around. Yes they may have won loads domestically and in Europe (including Rafa for that) but the rest of the PL was actually quite weak at the time.
Not only have we got excellent managers/tacticians come in but a lot of the same-old, same-old dross has actually been removed: Fat Sam, LvG, Martinez, Villa's Manager [insert name here], Moyes, Hodgson, Rodgers. Teams with interim managers years ago are even in a better state (Bournemouth, Southampton).