Elune was and is the core of their society. When the Kaldorei branched off from the rest of Night Elf society after the Sundering they just replaced arcane studies with nature studies. Their nation and capitol was originally called Elun'dris, then when Azshara came to power it was renamed to Zin'Azshari. The Tomb of Sargeras was the main Temple of Elune before the Sundering. The whole matriarchy aspect of Night Elf society comes from the Priesthood of Elune which was gender exclusive for a very long time.
The Night Elves continued to build elaborate structures, just refer to the Temple of Elune in Darnassus, as well as all of the ruins at Mount Hyjal. Hyjal was settled after the Sundering, everything there is what they decided to build after they broke away from their arcane traditions.
All of that being said, I would really prefer a new city to be a mix of:
and
I want to see some impressive and artistic tree-shaping to build a lot of structures, especially in the druid/hunter side of the city. I would then like to see more grandiose stone/wood structures for the Priesthood and Mage side of the city. I would then like to see a melding of both for the Martial side of the city where the Sentinels and Wardens train.
The Forsaken I'd like to see something like Menzoberranzan:
I'd like to see an underground city that they undead dig out for themselves like the Undercity, but with the intent of keeping it extremely inhospitable for the living. I'd like to see a bigger influence of the Cult of the Forgotten Shadow and less Scourge-like architecture. Essentially have the Forsaken lean more towards something like the Warhammer Dark Elves, and less like the Warhammer Skaven (which they currently take a heavy lean towards). I think one story reason for their new home is that the Forsaken find an old and abandoned city of the Black Empire, or something from the Aquir Empire that the Trolls drove them out of. The Forsaken take over that region and re-purpose it as their own.