The Windows SideShow Universal Driver does support USB, but that would require OTG mode. Yes, it's possible, but it's not really as user transparent as it could be. I don't think that it would make much difference to speed, TBH. Most of the delays come from SideShow, or the gadgets themselves.

One thing I've found while developing the app is that the available gadgets do things in very different ways. The SideTunes gadget, for example, has dynamic menus (each menu is loaded when needed). While the Microsoft Outlook Contacts gadget loads everything at once. If you have a lot of contacts, this can take some time.

I've seen similar issues with RSS feeds. The app simply doesn't get the data. So it's an issue with the gadget. It may have something to do with the RSS refresh times. It does eventually get data, you just have to be patient.