We’ve all heard countless opinions about whether Apple’s new, mid-sized form factor will be a hit. There’s no doubt that the iPad is a slick, sexy device, but I don’t think it will be an overwhelming success.

Even Steve Jobs acknowledged the fact that many people might place this device in a dangerous “in between” category – not quite portable enough to replace the iPhone or robust enough to replace the notebook. However, Apple responded by aggressively promoting an inexpensive wireless data plan model that undercuts all of the major carriers. This price, over the lifetime of the device, is an incentive to pony up the Apple premium price and reap the cost savings of the discounted wireless broadband service.

Now that we have some specific details of the iPad, I think it’s worth focusing on things that were not discussed during the Apple event. Most of these are related to hardware, but some of them are Apple hardware and software philosophy issues.

1. Limited I/O. Steve Jobs took a dig at netbook computers during the presentation, saying that there was no comparison, but this is the segment where the iPad will compete.

A subsidized, broadband wireless-ready netbook will get you a pretty loaded machine for a very reasonable price. Alternately, you could opt to pay the full price for a netbook and purchase a subsidized wireless broadband USB dongle. In either case, you’ll have to pay more for the monthly broadband service than you would for the iPad, but with this price, you get a tremendous amount of flexibility. For example, you can choose your carrier and the broadband device that hooks up to your netbook.

A base 16GB iPad is a locked-down, closed system. There is no ability (that was disclosed at the time of this writing) to add broadband wireless later. There are no standard USB ports. There is presumably no way to upgrade the base memory. For the entry level price of $500, this is a very limited device – and the only upgrade path is to sell the device and buy a better one.

Certainly, some people on tighter budgets who want a fruit on the back of their device will make this purchasing decision, but I think that most rational people are going to see this as a pitfall. By the time you work your way up to the 64GB device with built-in wireless broadband, you’re talking about spending right around $900 – not including the monthly service charge for the wireless broadband. That kind of money would buy a very nice laptop with broadband.

The closed, locked nature of the system, proprietary connectors, proprietary software market, and non-upgradable system architecture are a lot of deal breakers, in my book. Unless a device is driverless, you’re not going to be able to add it to the iPad without Apple’s approval, which means that certain devices are almost certainly out of the question.

The concern isn’t that these things can’t be done – it’s that you’re at Apple’s mercy if they will or won’t allow it. This design and deployment philosophy has plagued Apple since the earliest days of the Macintosh, and it’s one of the reasons PCs eventually emerged as more successful.

I expect to see Windows 7 and Android-based touch tablets with equal or richer feature sets and far greater expandability for a fraction of the price of the iPad in a short amount of time. Android seems to be the logical favorite to emerge in this market. In addition, wireless carriers will likely compete with comparable pricing plans for wireless broadband.

2. Application feature sets. I was surprised that the Apple event had very few minor talking-points before launching right into the iPad, and I was even more surprised about the iPad talking-points that Apple decided to highlight.

Perhaps the lengthy portion dedicated to iLife was to illustrate that the Apple iPhone OS could scale up to traditional, full-featured applications. And while Apple certainly has a good start on content distribution, I don’t see that they are building on the shoulders of the Amazon Kindle as they claim.

Digital books, in this segment, are not the killer app that Steve Jobs seems to think they are. The Kindle is successful for a couple of reasons. 1) The Kindle is a purpose-built device. Lots of other devices tried to deliver eBook and ePeriodical experiences before but were not successful. Apple hasn’t done anything significant in improving those models. Kindle did. 2) Kindle is a relatively small, niche market, mostly of very dedicated “used bookshop” readers. However, these insatiable readers are a declining breed. If Apple cannibalized the entire Kindle reader market, that would be a drop in the bucket compared to the number of iPhone sales to date.

I’ve been using this example: Do you know someone who is always carrying around a paperback, reading at lunch and on breaks? That guy is a Kindle candidate, because he’s excited about the prospect of having his entire library digitally available wherever he goes. Most of us, though, simply read in bed at night or take a book on a trip – maybe to read on the plane. We’re only going to need one paperback at a time – and this is why the Kindle remains a niche. Form follows function, and traditional print remains the most ideal form for most purposes for most people in most occasions. The Kindle doesn’t have enough value add for most of us, and the iPad will offer even less value.

I was impressed that Apple included the keyboard dock accessory. However, when I heard Jobs discuss how easily the iPad will interface with projectors for presentations, my first thought was that all of this will be handled through the single, proprietary Apple USB iPod interface, which to date has no “USB hub” option either. This kind of lock-in will hurt the iPad, and it could have easily been avoided – while still allowing Apple to maintain their iron-fisted grip on accessories – by simply including one or two standard USB ports. This is an oversight that Apple’s competitors will certainly not make in their upcoming products.

The advantages of the iPad are its user interface and the app store, things oriented toward less technically inclined users. But this particular segment – the “mid-range” PC that dumbs down the experience and makes it super accessible to grandmothers and soccer moms – I’m not sure they’re going to sign up for this device. I can’t see where the iPad hits the mark with consumers who are actually willing to pay between $500-900 for the device, especially as more compelling, feature rich, less expensive, gadget-freak oriented devices arrive. After all, casual users are content with the iPhone, which already offers the same advantages of the iPad.

Broadly speaking, this segment – new portable, consumer-oriented electronic devices – is on fire right now, but Apple’s model doesn’t lend itself well to consumer or partner freedom. In the past, it was almost sacrilegious to speak ill of Apple, and if you did, you were branded as being unenlightened. However, I’m struck by the number of Apple users who are now voicing their opinions in forums that they can’t wait to jump to Android and, more surprisingly, Windows 7 mobile, both of which look to offer very strong competition.

In the end, I think that the iPad will eventually be regarded much like Apple TV – a product that Jobs should have left on the drawing boards.