Split screen on the 9.7" would be appealing for some. Not for regular usages of course, but it would definitely boost my iPad work usage if I could have a web page or PDF open on one half of the screen while I type with an app on the other. I wouldn't routinely use it, but it is nice.
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Also, I fear that with the way iOS works, Apple would would boost the Pro to a none iOS ready resolution and use their "desktop scaler" that is used in the Plus. That would result in some bad UI lag/stutter on such a large scale. I know when (if) I updated my iPad 3, I'm getting the fastest model available with no scaling. I'm so freakin' tired of everything being so slow.