I think its fine to have a single picture for avatar and profile, its simple and nice.. otherwise it would be confusing.
Suggestion: If you really want to expend it then try adding a feature to store multiple (previously uploaded & new ones) profile pics same like facebook does. And option to select any of those as a profile/avatar picture
IP.Board have gone the other way and removed the twin image avatar/profile pic setup in 3.2 in favour of a single image, on the basis that it is less confusing; and I must admit, on my own IP.Board it is something that comes up quite often "I uploaded my picture but it's not appearing next to my posts".
I suppose if it is an add-on then site owners can chose to use it if they feel it is something they want for their site. Might be interesting to see if there is some interest for it - there may well be people migrating over from vB for whom it would be important to keep these two distinct images for users.
An easy way around this is to simply insert an image in the About You section in your profile, host it on photobucket or what have you and use the bbcode img function, the photo will be present in the Information tab