Microsoft's Surface: What's next, what's needed?

Microsoft's Surface tablet has been the focus of intense speculation in the past couple of weeks. What could be next and what's necessary?

       The Surface and Surface Pro lines are some of the best examples of tablets with detachable keyboards.

With changes possibly set to be announced by Microsoft on Tuesday, it's a good chance to take stock of Microsoft's first full-fledged PC.

Let's begin by saying that it's hardly clear at this point what Microsoft will announce. The company has sent out invitations for a "small gathering" on May 20 in New York City.

That has triggered a rash of speculation that the event is centered on a Surface Mini. But what I am hearing is that the Surface Pro will get some internal Intel Has well-based tweaks. (Update: a possible larger design, maybe 12-inches, could come Tuesday or later.)

But let's put aside the question about whether Microsoft will announce a Mini (or not) but, rather, ask: does Microsoft need a smaller Windows RT 8.1-based tablet?

Mini mania passed: One obvious problem is that a Mini would be very late to the 7- and 8-inch tablet party. That fad has passed (even Apple's iPad Mini is now losing ground to its larger cousin, the iPad Air).

As tablet growth rates drop like a rock, momentum in corporate America is shifting toward larger "productivity" tablets and hybrids like the Think Pad 10, Dell Venue Pro 11, and Samsung Galaxy Tab Pro 12.2. And don't forget that Apple is rumored to be working on a larger tablet for professionals.

So, would it be worth Microsoft's while to devote considerable resources to a small tablet, if the market is past its prime and the device is running the unpopular Windows RT operating system, to boot?