What I think would sell well for every city collector are City 'filler' sets containing items to make a better layout and to provide more accessories. Previous examples of this have been very poor with very few minifigures (not to mention repeats of figures which come in every other set). A couple of sets with trees, flowers (include new orange and light blue colours), benches, a statue, new colour bicycles, lamp posts, traffic lights, fences, new hedges, roundabouts, bus stops and signs.
If this was combined with a new selection of a lot (say about 30) new figures not included in any other sets at a decent price I am sure every City fan would buy a copy. They could even theme each pack...
Summer In The City, minifigs in T-Shirts and shorts, girls in summer dresses, a small ice cream stand, plenty of flowers.
Winter City, minifigures in warm clothing - hats, gloves and scarves, snow covered trees, kids with sledges, a snowman
City Business District - figures in office attire, mobile phones, laptops, briefcases. Other figures dressed as civilian employees like waiters and fast food workers.
Other options could include a school set, a farm expansion pack with sheeps, goats, pigs, cows, chickens - basically anything except for police, fire and construction!
Edited by lifeinplastic, 18 March 2012 - 08:46 PM.