The Wall Street Journal earlier this week took the contrarian view that the iPhone has not really been that great for AT&T after all.

The carrier has seen improvements in some important areas such as churn rates (compared with previous rates and industry average) and average revenue per customer (stands to reason with higher data plans). But the overall new customers AT&T has gained from the iPhone is only about $4 million, or 5 percent of its subscriber base.

The biggest downside has been how the iPhone has caused a drag on its network speeds and has brought to light its network deficiencies. The question is whether 4 million new users are worth the ever-worsening PR lashing AT&T is taking. TechCrunch and GigaOm coverage alone has made this question worth asking.

Ultimately it’s hard to feel sorry for the carrier: A better technology revealing the deficiencies of your own technology (network) isn’t going to earn sympathy among media, consumers and digerati. The iPhone brought these to light but they were there to begin with.

Meanwhile, AT&T continues to be a bottleneck for some of the functionality released with June’s iPhone 3G launch and the question remains whether the carrier’s iPhone exclusivity will renew past next year’s contract termination (I think no). Verizon’s 80 million subscribers and and expected LTE network rollout loom on the horizon.

Beyond the carrier/consumer angle, all this has important implications for the iPhone’s reach and abilities — and thus its attractiveness as a development platform. The choice of platform (native app, SMS, mobile Web, etc.) will continue to be an important one for the rapidly growing subset of media companies looking at and jumping into mobile.