The rumoured Nexus 10 2013 refresh remains an intriguing mystery as Google has yet to hint of any solid clues that release date of the supposed iPad Air killer is coming very soon.

Or it may not come at all, at least in the current year, as Google shifts its attention to another tablet form-factor. The reason for the surprise re-gear is the emergence of 8-inch slates as the fresh consumer magnet, CNET said in a report.

It used to be that 7-inch tablets were seen as strong challengers to the iPad dominance and for some time it appeared that as Google and Amazon attracted significant attention with the initial builds of the Nexus 7 and Kindle Fire.

Pundits started discussion threads that floated possible iPad killers. Indeed it came just before 2012 ended but it was Apple's creation too - the game-changing 7.9-inch iPad Mini.

The specs that it came with were moderate, at best, but the Mini sold in big numbers. More importantly, it allowed Apple to again redefine the tablet market and industry players started to look at the iOS compact tablet as the device to beat.

Meanwhile, the original iPad may have taken the backseat as the Mini continued soaring but it maintained its firm grip in the so-called upscale tablet market segment. Contenders like the Galaxy Note 10.1 from Samsung and Nexus 10 from Google (but made by Samsung) came to skirmish with the 9.7-inch tablet leader but to no avail.

Apple continues to hold sway in the large-screen tablet class, luring more and more premium buyers.

Dealing with this reality, Google could possibly nix its planned Nexus 10 refresh for 2013 or at least delay it arrival until next year. The aim is for the search giant to reconfigure its tablet business model, CNET said in a separate report.

"I think the lack of a Nexus 10 refresh (at least to date) reflects the fact that the market for a premium Android tablet is still pretty small," IDC analyst Tom Mainelli told CNET in offering his explanation on why the second Nexus 10 will not touchdown this Q4 2013.

In its stead, Google is likely building a more attractive alternative, which recent reports suggested as the yet to be confirmed Nexus 8.

The move makes sense - the form-factor is popular these days (the iPad Mini is such a big hit) and Google has the room to manoeuvre the Nexus 8 in tackling its rivals, chief of the Retina-flavoured iPad Mini 2.

No definite details have been connected to the Nexus 8 but many believe it will be a better version (not necessarily more powerful) of the recently released LG G Pad.

And Google is not alone on its thrust to topple the iPad Mini (and the iPad Mini 2) from its throne CNET said. Popular PC brands like Acer and Lenovo have been rolling out Mini foes in succession.

However, the most notable efforts remain coming from Samsung with its Galaxy Note tablet series and the Galaxy Tab 3 family. The Note tablets, specifically the Galaxy Note 8.0, has been gaining some ground partly on its unique S Pen feature. Native stylus support is yet to be introduced by Apple on its iPads.

So the full-sized Nexus 10 2 release date may or may not come at all but when the latter happens, Android fans can at least look forward to the possibility of a Nexus 8 surfacing just in time for the holidays.