My suggestions :

1)Remote upload and possibility to upload from other filehosts/torrents ( user provides premium account and host leeches from there ) just like filefactory ... register and you will see

2)For free users the best thing it would be to limit just the speed ... and no stupid countdowns

3)Total privacy for uploaders ? I guess that would be too much from the legal point of view

4)Reward system but with more than one payout method ... paypal brings lots of headaches

5)Hosted Offshore

6)Light design , no complicated bullshit