It feels old because it hasn't changed in 5 years, but I personally appreciate that. All of the original mechanics make perfect sense, and the new mechanics (such as app folders and multitasking) have been introduced in a way that minimizes interference with the existing look and feel. As someone who uses a lot of music production apps that can't talk to each other, I do wish there was something like a filesystem, but I also want it to be introduced in a way that does not change the basic look and feel of the device.

What's amazing is that an original iPhone and iPhone 5 look and feel largely identical for basic uses, even though the latter is a far more capable device. That's a testament to the strength of the original design.