Gamereactor has a preview on Civ5, published 6th of April, you can read it here.
Not with much new stuff in it, but this may be an interesting quote:
"Firaxis opted to limit the number of units occupying one tile to simply one this time around,
with cities not being able to host any units at all."
Origineel Artikel: http://forums.civfanatics.com/showthread.php?t=360537&goto=newpost