What does "not optimized for tablets" even mean? It's stretched out? Pixelated? Black bars? I would think it wouldn't be that bad on the 7 inch form factor of the nexus 7?
It means that it was designed to use the screen real-estate of a tablet PC, not simply stretch the smartphone interface across a bigger surface area.
For example, OneNote for iOS has a Ribbon Interface on the iPad which makes it a complete joy to use, while the Android version is simply a blank slate smartphone interface stretched across a larger surface area.
Facebook for iOS has both side bars visible on the screen along with the stream in landscape mode on the iPad, because there is room for that on a tablet and it's simply a superior way to display things on that screen size. The Android app is still simply the smartphone app - stretched across a larger surface area.
Twitter for iPad puts the navigation on the left side of the screen and gives more room for content, among other things. The Android app on a tablet is simply the smartphone app blown up.
Most 3rd Android apps do not have a proper tablet version, but those same apps have a proper iPad version.
There is a difference between "Works" and "Designed for." Those iPad apps are designed for the iPad, and work better than their Android counterparts in almost all cases.
I do have a few apps that are Universal on Android. OfficeSuite Pro, Pocket, and Skype for example. But 90% of the 3rd party apps I installed and ran simply presented a blown up smartphone interface, and I don't like a lot of the third party Twitter/Facebook clients, among other things, because those developers don't know how to design a decent user interface (often too busy, bad themes, etc.) - nevermind there are features missing (Facebook Voice Calling, some Messenger Features, Twitter Push Notifications that no third party app is as good at doing, etc.) and feature implementation lag.
Lastly, a device with locked storage (any Nexus) has no room for redundant applications. I'm not ditching the Official, and I don't see a need to install a worst third party app (in overall functionality) in addition to it.
So I'm not touching Android tablets until the developers start pushing out quality tablet apps, like on iOS/iPad.
I'm up for upgrade soon, so buying on two platforms can potentially not be an issue for me...