The tablet wars are heating up between two tech titans: Lenovo (LNVGY -1.24%), the largest PC maker in the world, and Apple (AAPL -0.74%), the top tablet maker in the world.

Lenovo recently unveiled the Yoga Tablet 2 Pro, a 13.3-inch Android tablet with two 1.5W front-facing speakers, a 5W JBL subwoofer, and a built-in projector. The device was reportedly designed with input from Ashton Kutcher, who has been channeling Steve Jobs (whom he portrayed in Jobs) after being hired as Lenovo's spokesman and "product engineer" last year.

Apple unveiled two tablets at its iPad event on Oct. 16: the 9.7-inch iPad Air 2, which is 18% slimmer than its predecessor, and the 7.9-inch iPad Mini 3, which features Touch ID and slightly better cameras. The long-rumored iPad Pro, which could have a 12.9-inch display, was noticeably absent.

Lenovo's Yoga Tablet 2 Pro. Source: Lenovo

Comparing the Yoga Tablet 2 Pro to Apple's iPad Air 2 raises some interesting comparisons. Whereas Lenovo is storming ahead with daring designs which may or may not resonate with users, Apple's new iPads felt uninspired.

Apple has struggled with declining year-over-year iPad sales for three consecutive quarters, with shipments falling 13% last quarter to 12.3 million units. That makes it vulnerable to disruption from hungry new competitors like Lenovo, which previously toppled PC titans Hewlett-Packard (HPQ -0.23%) and Dell with its convertible Yoga laptops.

Should Apple do more to defend its iPads, which accounted for 12.6% of the company's top line last quarter, from Lenovo's new tablets?

The curious business of bigger tablets
Despite Apple's troubles with the iPad, interest in other tablets isn't declining. Gartner forecasts that global tablet shipments will climb 11% year over year and hit 229 million units in 2014. While that's a disappointing drop from the 55% growth in tablet sales between 2012 and 2013, it doesn't explain why Apple's iPad sales are falling year over year.

The problem with Apple's tablets is that smaller models, like the iPad Mini, are being gobbled up by phablets, while larger ones, like the iPad Air, face significant competition from two-in-one devices like Lenovo's Yoga Pro 3. Apple itself is contributing to this problem with the iPhone 6 Plus, which will likely cannibalize sales of the iPad Mini 3.

That's why companies are experimenting with new screen sizes and form factors. Since the 6- to 10-inch market was saturated by smartphones, phablets, and tablets, companies launched a flood of larger all-in-one devices last year, like Dell's 18.4-inch XPS 18, Sony's 20-inch VAIO Tap 20, Asus' 18.4-inch Transformer AIO tablet, and HP's 20-inch Envy Rove. While those devices were decent desktop PCs, they failed miserably at being tablets due to their size and weight.

HP's Envy Rove. Source: HP

A 13-inch tablet, which is the size of a midsize laptop, seems to be more practical as a portable device. However, 13-inch tablets don't feel necessary when compared to lightweight 13-inch laptops or convertibles. That's probably why Lenovo added a built-in projector and impressive sound system as additional incentives, and why Apple is reluctant to launch a comparable device.

Yoga Tablet 2 Pro vs. iPad Air 2, by the numbers
To see if the Yoga Tablet 2 Pro can actually steal customers away from Apple, however, we should take a look at how their specs stack up against each other:

 

CPU/RAM

Battery

Weight

Cameras

Extras

Price

Apple iPad Air 2 (9.7 inch)

64-bit A8X, 2GB

10 hours

0.96 lb.(Wi-Fi)

0.98 lb.(Wi-Fi/Cellular)

8 MP rear, 1.2 MP front

Touch ID

$499 (16GB Wi-Fi) to $829 (128GB Wi-Fi/Cellular)

Lenovo Yoga Tablet 2 Pro (13.3 inch)

Intel Atom Z3745, 2GB

15 hours

2.09 lbs.

8 MP rear, 1.6 MP front

Projector, subwoofer

$500 (32GB)

Source: Company websites

The Yoga Tablet 2 Pro is more than twice as heavy as the iPad Air 2, although it offers a larger screen, 50% better battery life, a better front-facing camera, and a built-in projector and subwoofer. Moreover, the $500 model offers twice as much internal storage as a comparably priced iPad Air 2. That could be enough to steal the spotlight from the iPad Air 2, which only offers incremental improvements over its predecessor.

Apple's simple strategy of product line refreshes worked in the past when demand for iPads was strong. But now that demand is declining, Apple needs to do more to show both existing iPad owners and potential new customers that the iPad Air 2 is worth buying.

The takeaway
The iPad looks like it's headed down the same path as the iPod. It will be slimmed down in different colors, but demand will drop off as sales are cannibalized by other products and current users stop upgrading their devices every year.

Lenovo's Yoga Tablet 2 Pro might not wipe out the iPad Air 2, but it's certainly more innovative than anything Apple showed us on Oct. 16. If Lenovo starts to get even crazier with its designs -- such as slapping projectors and subwoofers on smaller tablets -- Apple could lose market share in tablets a lot faster than investors expect.