Well, the answer is that it actually does work - if your remote control has keys that map to keyboard arrow keys and "enter".
Many WMC remote keys are meaningless to Windows (the OS) so they won't work in Metro. When companies make remote controls going forward they can just make these remotes appear as a keyboard (to the OS) and map whatever keys or key combinations that Metro will respond to.
Why don't we see this yet? Because Metro isn't out yet - but there are hardware/software product combinations that I'm pretty sure you could get it to work today without any "products from the future".
That remote to keyboard command map is a little misleading because it implies that, say, the "ok" button (VK_RETURN) is the equivelent to the Enter key. While WMC does accept both the keyboard enter key and VK_RETURN key on the remote as the same command (to "drill down" on the selected menu item), that doesn't mean that from the applications perspective that the input is the same.
In other words, if you load Microsoft Word and try a lot of those WMC remote keys, you won't get "enter" or "arrow up", etc. WMC is just very accepting of different many different possible inputs.
For instance, you can decrement the channel number by pressing:
Channel Down (remote)
MINUS SIGN (-)
All those inputs do the same thing, but that doesn't mean that the remote key will necessarily cause you to see a "-" character appear in Microsoft Word.
I should note that I've discovered an amazing lack of consistency between WMC remotes that I have used over time. Some remotes will send a APPCOMMAND_MEDIA_CHANNEL_DOWN message to Media Center while others are actually just mapping to the PageDown key.
Alot of people simply rely on apps like EventGhost to control everything(VLC,NPVR,WMC,MP,Explorer and the like).
If you can use a key to do it EG can "make it so".
And hence select the application specific command that suits the use regardless of the remote.
Or just move the bloody mouse and left or right click
I have a Hauppage MCE remote and using my EventGhost profile for NPVR the "clear" and "enter" buttons are mapped to mouse left and right clicks.
This is useful in NPVR because a right mouse click brings up the "settings" menu(even while watching TV or video). I can select audio or subtitle stream or go into full settings menu and do a channel scan or tweak a decoder. There are also the rare ocassions when I may want to open windows explorer or control panel or navigate my desktop. Granted it's rare but I can do it.
I always said Microsoft should strip the crap out of Windows to make it a barebone OS and offer module for micro-transaction. Customers would get a more snappier OS and likely a more solid and secure ecosystem. You give away the razor then you sell the blades!