I don't know what kind of warlock you play, but detecting invisibility and unending breath are part of mine. I think unending breath is still pretty useful, but apart from that, it's definitly something that made the warlock unique.
It's not the end of the world that they are gone, but the OP has a valid point, why on earth remove them? It's not like they were imbalanced or buggy. It's like taking a priest's levitate.