I tend to look at life very dialectically, so pleasure only means something when contrasted with suffering, thesis when contrasted with antithesis, master vs slave, etc. So a state of absolute unity, where both sides of the duality collapse, ie man into God, subject into object, must be a state where experience is no longer possible, and hence a state of emptiness.
Of course if becoming one with God meant becoming God and still being aware of people beneath you, the duality would still be intact and experience could continue, only now you´d be master instead of slave
