From how it appears right now, it's not. All indications show (although nothing's been officially announced) that Kumo is a codename for changes they're making to Live Search (particularly around the layout of search result pages), not a completely different search engine.
I hope they change (improve) quite a bit more than the layout - screenshots of which look unimpressive. I think they look fine, but boring.
Live Search has been getting consistently better since it came out. Unfortunately, Microsoft started out 18-24 months behind Google (made up estimate based on my subjective and flawed interpretation of their respective search qualities), and they've stayed at least a year behind since. Google has matched or exceeded Microsoft's investment into search - moving into more areas of vertical search/etc - while Microsoft has done nothing special. Indeed, Microsoft has closed off vertical search products which compete with Google (book search, academic, etc).
WolframAlpha looks cute, and it's the type of experiment Microsoft should be performing. Or doing things that Google is doing - which is taking more risks with its search results, such as voting on links or adding notes - for all Steve Ballmer's claims that Microsoft is taking more risks. Microsoft is doing, or at least has done, nothing of the sort.
In any event, I currently expect Kumo to be disappointing - to move the bar forward a little bit, but still remain behind Google. A design change does not a product change make.