If Linux wants to make it into the mainstream then this has to be the way to go and it can be installed this way it brings into question what all the partitioning is about in the first place ?
There's a few reasons. 1) A problem with one isn't likely to hose the other, 2) most filesystems are better than NTFS (or at least better than how Windows' file manager handles NTFS), 3) Linux has better access control and file locking (for example you can update Linux files without having to reboot for trivial things like browsers, graphics drivers etc etc) which is better run on a proper file system.
And 4) when people do decide they really want to be rid of Windows (not all of them, though Q4OS might make it a lot easier for some) and want to recover the space, it's a "simple" matter of deleting the partition (or how I normally do it, delete the entry from grub (etc) and give them another week or two).
It's why a lot of systems advise keeping user and OS stuff seperate as well, to help avoid total loss. Acer systems and a few others (iirc) used to come with the HDD split into 2, d: being for data (but very few people every used it, giving you a great spare partition to install Linux on :)
A lot of people switching from Windows to Linux will have someone who can help them through the experience. They don't need to work through the harder stuff.
But for those who don't, then certainly having something like this could at least be a start. But I've seen issues with running 2 os's on the same partition, although being very different in this case (ie not 2 *nix or 2 windows) means you don't have 2 things wanting to use the same data dirs.
HTH, and hope someone can explain it better (neighbours had a rough night)
Biting the hand that feeds IT
