It's never too early for the Apple (AAPL 0.36%) rumor mill to start churning. The latest rumbling is that the iPad maker is set to unveil a fifth-generation iPad in March, just over three months from now.

Japanese site Mac Otakara believes that the device will soon get an industrial redesign and look similar to the current iPod Touch and iPad Mini. March would be just five months since the launch of the fourth-generation model. The site also believes the iPad Mini will get updated with a Retina display and use a similar A6X processor as the current full-sized iPad.

Almost immediately after launching a pair of iPads in November, are new ones already imminent?

Why ask why?
The iPad product cycle is entirely up in the air right now, since the fourth-generation launch was just seven months after the third-generation model and a stark contrast to the one-year cycles the device has seen thus far in its short history. However, the case for an immediate fifth-generation iPad isn't very compelling.

First, let's look at why Apple risked spurning early third-generation adopters with the prompt fourth-generation update. The three most notable changes in the fourth generation model were the A6X processor, expanded LTE coverage, and Lightning dock connector.

Moving to the A6X was important because it utilizes the first custom ARM-based (ARMH) core that Apple has created with its ARM instruction set license, code-named "Swift." That's how the processor is able to boast double the performance relative to the two ARM Cortex A9 cores found in the A5X. This CPU debuted in the iPhone 5, but including such dramatic performance improvements in the iPad would be greatly appreciated heading into the holiday shopping season.

In the cellular-equipped models, there was an important transition to the newest Qualcomm (QCOM -0.47%) baseband modems built on the more power-efficient 28-nanometer process. The third-generation LTE iPad carried a first-generation Qualcomm MDM9600, with the fourth-generation model is believed to be sporting a similar second-generation baseband as the iPhone 5. That's why the LTE compatibility is nearly identical. That improves battery life while broadening its appeal in international markets, again ahead of the holiday season.

The Lightning connector transition is less meaningful, but switching to it allowed Apple to complete the change quickly after starting it with the iPhone 5. The company will probably utilize this connector for the next decade (after the 30-pin dock connector lasted a solid 9 years), so it might as well get the transition over with.

Say it ain't so
None of these reasons for redesigning would be true for a fifth-generation iPad. Even if Apple has an A7X processor ready for prime time, it would likely save this ammo for another day considering the performance gains in the A6X. Besides, chances are the A7 and A7X aren't fully baked yet, anyway.

Qualcomm's third-generation basebands are sampling in the fourth quarter for 2013 product roadmaps, but I highly doubt we'll see any products with these chips in the first quarter. One of the features of this new chip is support for LTE Advanced, which is nascent. Russian carrier Yota just launched the world's first LTE Advanced network in October, and there aren't even any devices that support the standard yet. The point is that there's no major connectivity incentive to rush out a fifth-generation iPad.

It's still entirely possible for Apple to update the full-sized iPad in T-minus three months, but there doesn't seem to be a lot of reason to rush. The next model should see an industrial redesign, but that's hardly a time crunch. It also seems just as likely that Apple's just shifted its annual cycle and iPad launches will coincide with iPhone launches in the fall.

Two back-to-back product cycles of approximately half a year? Seems unlikely.