To me Man of Steel is very much a Superman movie that would fit into the Nolan's Batman universe, it has the same tone to it.
In my mind they didn't use Man of Steel to establish any 'new' DC universe, it just followed on, it was very much a Nolan Superman movie too.
I'm fine with Bale not returning, he hung up his cape... and ok don't bring back JGL...
But for people to say they are opposed to the two worlds being linked, and that they can't bring back JGL because then they'd have to carry on that type of gritty realistic superhero movie baffles me, because they already did it with MoS.