The reason why 'Movie Maker' is not with Windows 7, is because there can be more free space and Windows 7 used less memory than Windows Vista. Windows Vista had a lot of junk programs that nobody hardly used them so Microsoft got rid of them in Windows 7. You can download 'Movie Maker' by using Windows Live Essentials.
Windows Movie Maker for Win 7 absolutly does input .mov files. I don't know about Movavi, but your probably right about it being better than Movie Maker. Although, this version is better than Movie Maker for XP.