When you think of current devices, you probably think of the iPhone 5 and the iPad 4th Generation. But there are other devices still being sold as new. And there's a shocking number of apps that are not properly tuned to work properly with these other new devices.
The iPad mini is a brand new device. And it's damn sexy too. It's basically the same internally as an iPad 2. Both the iPad mini and the iPad 2 are current models for sale by Apple. In addition, the iPod touch, while it sells amazingly well, is a generation behind in hardware and often a second thought for support. There are just way too many apps that operate slowly or crash when running on these devices.
It's important for developers to support the full range of current devices not only being sold, but also being supported by Apple. Basically if it runs the latest version of iOS, it should be supported in apps. It's possible to support the range in all but the most extreme cases--many developers do it. Unfortunately, some developers are lazy either in their support or in their testing for these other models.
So, consider this a call to action for users and developers. See an app that doesn't work well on the iPad mini, iPad 2, or iPod touch? Head to the App Store and hit up the support link for that app and let the developer know you noticed. Maybe then we'll see better support for all iOS devices, not just the latest and greatest.