I'd like to see more decorations, different colour flowers and maybe even snow (since we are getting so much of it) and some pedestrian walkways, like cobble stones or gravel.
A road bridge so cars can travel over the water I place in the city
Football stadium (soccer) nothing too small a 3x3 would be good
A new wonder would be good, something from London ? Like the Gherkin or Big Ben or even Wembley stadium !