My 9-year-old daughter got the Friends Brickmaster book and in it Mia and her friend build a raft and explore an old mine looking for buried treasure. It really fired up her imagination and reminded me of the Nancy Drew books that I loved at her age. So, I'd like to see the Friends sets introduce more intrigue and adventure over shopping opportunities.
I like ideas others have said like a zoo, museum, winter sports. Other ideas might be: amusement park or county fair, observatory, theater, costume party, snorkeling.
I'd even like to see the Friends world expanded and see the girls take a trip outside Heartlake.