USB Host Stack development for embedded domain

Hi,

We are trying to build a commercial grade USB host stack.

For this host stack to be one among the many available in the market, we came up with the following feature set.

1. Support all four transfer modes.
2. Support hot plugging
3. Support mass storage, hub, HID, printer, audio and video class drivers
4. Support USB 2.0 high speed data transfer
5. Portable to different CPU arxhitectures
6. Portable to different RTOS
7. Support OTG

I would like to know if any other feature should be included so that this USB stack which we are developing is one among the commercially available stacks.

Thanks, pri