Would be cool if Avast had a Windows 8 gadget (computer) on the start screen for windows 8 rather then having to go to desktop 
They do but once you click on it you’ll be taken to the desktop anyway, it would be pointless and time consuming to develop two separate UI’s, especially when there is no discomfort in using the standard one.
Or do you mean a live tile which would just supply basic information ? that wouldn’t be a bad idea.