Norgannon gave Nozdormu some of his power, Norgannon also sees limitless timeways, as does Valen.
Im positive the titans, if not at the very least Norgannon knows of Segaras and of all the bad on Azeroth.
By saying apparently unaware blizzard isnt being definitive on the titans actually being unaware.
I think by saying apparently unaware, is to give a sense of being alone to fend for your selfs, as in the titans know of the events occurring, but dont care, or are to busy, as is they were unaware.
Anyhow by saying apparently, blizzard has not been definitive and thus your only speculating.