I like 1x1 buildings, city becomes more "colorful". Also 2x2, but only if they bring some coins. Those with 24/48 hours and 120/180 coins, i do not like them. 3x3 are a bit too big, imagine to have a city with 6 Pyramids...I think land expansion is another money maker.. Noticed how the end of quest/challenge buildings are all 2x2 or 3x3...... Originally they were 1x1
There was this post few days ago (by Deetee04

So, hope for more interesting new buildings in future, and also land expansion.
There should be possibility to buy 1x1 of land, or 2x2... And to have some missions / quests, that a reward would be land!