The explaination given during one of the PLLs for delaying the introduction was that if Novus was introduced as it originally was, the Atma/Animus grind would've been considered a walk in the park and they felt that was a bit too masochistic considering all the outcry on the forum. I'm guessing it was purely a FATE thing.

Surely, besides just adding more ways to get alexandrite, they had to tweak other numbers as well. You don't just turn on the taps without widening the drainage pipes.

I'm guessing the maps weren't necessarily made up from scratch, they did say that the mob hunts in 2.3 would be difficult to solo even for people in i90, some would require a bird and some would require a party. There are also reports on the JP side of the forum that some monsters have never been seen before. It's possible some of those monters actually are from the incoming mob hunt dailies.