The iPad launched in 2010, and one of the original selling points of the device is that it could run all iPhone apps out of the box. It took awhile for iPad apps to get going, and having the ability to run iPad apps allowed users to have their favorite apps, while waiting for updates. It’s now 2016, and most apps are universal, or at the very least have a separate iPad version. There are still a few outliers, but for the most part third party developers have done a great job of supporting the iPad. Apple on the other hand hasn’t supported the iPad as much as it could have.
To run iPhone apps on the iPad back in 2010, you simply downloaded the apps, and iOS automatically opened the apps in native resolution on the iPad. You can press the 2X button in the corner to double the resolution, but the pixels are blurry as you’re blowing up the 480:320 imagery. The iPhone 3GS and iPhone 4 were the main iPhones in 2010 with both offering a 3:2 aspect ratio, and consequently, that’s what the iPad used when running iPhone apps. In 2016, the main phones are the 6 & 6S with both offering 16:9 displays with much higher resolutions. The iPad though, is still running the same 3:2 aspect ratio when running iPhone apps with the 2X mode.
It has been six years, and Apple hasn’t updated the way you run iPhone apps on the iPad. Over the past six years, we have seen retina displays come to the original 3.5” screen, and expanded to 4”, 4.7”, and 5.5” iPhone screens. The iPad has gained its own retina display, and there’s even a “Pro” version of the iPad. Developers have had to update the art assets and UI elements multiple times over the past six years to support the changing resolutions and iOS device sizes. All of these additional art assets for different iPhone models could run in full resolution on the iPad for a practically native experience, just with letter boxing on the side due to the difference between 16:9 and 4:3 aspect ratios of iPhones and iPads. Sadly, Apple is still doubling the old iPhone resolution. Granted, they have updated the 1X iPhone version from 480:320 to 960:540, but now they’re just doubling that.
There are many fewer iPhone only apps to the point that you can forget that Apple hasn’t updated the iPad functionality. When you do come across it, Apple is presenting a sub-par user experience. You’re given blurry versions of iPhone apps with the cramped iPhone keyboard stretched on to the iPad display. It’s mind boggling that the 1X mode even exists, and even more problematic to see the 2X mode not using the full resolution imagery in the app files. Developers need to support the 6S Plus, and all of the updated assets could run on the iPad as it is with letterbox. The letterboxing is still there with the lower resolution assets, so it makes no sense not to include the higher resolution.
The worst part is that Apple isn’t keeping this around as a feature, but rather keeping it around because they have forgotten it exists. Hopefully you use universal, or iPad only apps.