Djokovic did win a good no. of them when both Nadal and Federer were fit/not aged and Murray was also fit. Plus the next tier of players including Wawrinka, Ferrer(few years back) and some new ones are good. The overall pool is definitely better imo compared to era when Fed dominated and even for a decade before that when any random guy used to win slam in between.
Djokovic's one slam win is against Tsonga (that type of player, 2nd/3rd tier), rest all are vs Federer, Murray, Nadal. Compared that to Fed who has final wins against likes of Baghdatis, Phillippoussis, Fernando Gonzalez(!), Soderling etc. I am not even counting one win vs almost retired Agassi, couple against Roddick (who in current era will struggle to be in top 8), Hewitt (no better than Wawrinka).