Only used the iphone version
1) 3-4 "fake" brokers with % or flat fee/per trade. Free trades/no fees/no minimums right now...
2) Margin and credit
3) Purchase price while looking at the portfolio
4) Instead of big loading screen, reduce to smaller size and do it in the background. "last updated time" at the bottom
5) Live stock ticker feed at top (just for fun)
6) Online counterpart for more detailed info (I know, pushing it right?)
Overall, its still really fun. It updates very quickly. And its free...but hopefully you have seen some return with the ads for future development!