Microsoft should (not really) have made a "Metro" Office (You people should read more carefully.)
EDIT: I am reading some of the responses and I am not sure people are getting it, so let me clarify. I disagree with the title of this post, and the rest of the post is my response to people who hold that viewpoint.
I see all of these people talking about the desktop being in Windows RT and complaining about this as a feature. The complaint will usually include someone talking about how having the two different interfaces will be jarring and that if they were going to clean-start like they are with Windows RT then it should have been 100% new interface.
The argument gets brought up that the desktop is a feature you can ignore if you want but it allows for things like advanced settings, file explorer, and most importantly Office.
The thing is making Office into a Modern style application would have been completely unfeasible at this time.
Think about everything Microsoft has going on right now. Windows 8 has taken up the last three years of Microsoft's time in a big way. The Windows team grew, which pulled a few people from other places in the company, to make sure that this near-total overhaul of an OS would be solid from day one. Not to mention the fact that there was a new team within the Windows team now working on a version for ARM (which is more complicated than just recompiling the source code for ARM). Combine this with the fact that there are probably people on the Windows team working on SP2 for Windows 7.
Then you have Windows Phone which is itself getting an overhaul this fall. WP8 is getting a whole ne kernel. Changing the kernel of an OS is more complicated than just throwing a new kernel into the old code. You don't have to rewrite the whole thing, but there reasons for the compatibility issues between, for instance, XP and Windows 7. Not only is there the new kernel, but there are all of the really solid new features coming to Windows Phone too. This is also combined with the fact that there must be a team working on WP7.8, and all of the work that goes into OEM relations.
To keep this brief I will skip to Office, even though there are plenty of other things like Xbox (not just the new console but also the upcoming update) and Surface (a first time thing for Microsoft, and one of the biggest deals in the company's history).
The Office team when working on the next Office had a lot of things to concern themselves with. It was only two generations prior that the Ribbon was introduced as the new way of interacting with Windows, and if they changed that now they would likely give Microsoft the reputation of changing interfaces every six years. They also knew that touch was coming, but that the vast majority of people would still choose to use their products with keyboard and mouse. They knew that cloud features were going to be better implemented and so there would have to be not just networking code but tons of security built in. They knew the Start Screen was coming, and with it there would be all of these new Modern-style applications, but that this new version of Office had to work for older versions of Windows too.
Given all of these things, there is no way they could have built just a Modern-style suite of Office. But why couldn't they do a Modern version also? Office is a high quality product. It is the de facto industry standard. Any product that comes out that bears that name must be good enough to. With the number of people within Microsoft who are devoting their efforts elsewhere, I seriously doubt there was enough manpower to do anything close.
You get OneNote MX, which is a glimpse of things to come for sure. But to complain about the interface in Office on Windows RT is to completely misunderstand literally everything about why it is that way.
I am interested to see how many people reply to this post after only reading the title. Hint: I am arguing against the point made in the title.