I agree with Zimnel. Ayleid Ruins weren't built for random adventurers to find their deaths in, they was supposed to be a place to live in, in the past. The design should reflect that. Like how you can find beds, chairs, tables, cabinets and all those things in Dwemer ruins.
This. Ruins need to be something other than winding hallways filled with traps. I would love to see ruins that look like actual ruins, with visible separate buildings buried together, different layers of occupation, the remains of a culture. This means more logical exterior ruins, too.
To elaborate on what I want:
-Exterior ruins that are either http://gordonbrentingram.ca/photobased/wp-content/uploads/2008/11/14-tanuf-ruins-bombed-by-uks-raf-1957-9-photo-by-gordon-brent-ingram-1-2004.jpg or show evidence of http://www.nationalgeographic.com/history/ancient/images/ga/masada-ruins-430519-ga.jpg.
-Several distinct types of ruins - large city, plantation, trading outpost, temple, etc.
-Multiple interior sections not divided by depth. For example, the interior ruin could consist of the remains of an underground temple, the palace's dungeon, and random cellars linked together to form a honeycomb of buildings rather than hallways linking big rooms.
-Rubble piles, broken pottery, roots breaking through, and other signs of natural decay. Balance this out with demolished buildings, violated religious statuary, carve anti-elven graffiti, etc, to infuse each ruin with a sense of how the city died.
-Cultural stuff specific to the Ayleids. Special pottery, items of religious significance, cool Art Deco Varla stone decor, slave torture and restraining devices, etc.
I would still like to see puzzles, though. I've always been a fan of puzzles/traps created by time, such as collapsing ceilings/floors, round-about ways to get around a broken section, maze-like beams/columns/bridges, etc. More traditional puzzles/traps would be appropriate in ruins that are meant to be temples, dungeons, or tombs.