This is the thing that most people don't seem to understand.
Just because you don't need a certain feature, doesn't mean that lacking that feature is a good thing for the OS. Some people will use that feature, even if you don't. Personally, I store a lot of long videos and lots of images on my phone. And if I want to delete one of those large videos, especially a format that's unsupported natively that won't get listed in the native videos app, I have to plug this in to a PC to delete it.
And then consider setting a ringtone. If you have an MP3 file on your phone that you want to use as a ringtone, WP forces you to plug it into a PC and then copy it into the ringtones folder. What is this nonsense? Even my old S40 Nokia could set any MP3 file that's on the phone as a ringtone or an alarm tone. If there was a file manager capability, this copying could be done without a PC.
Now you may not need these feature, but saying that they're unnecessary just because you don't need them is the absolute height of ignorance.
Oh, and I saw someone talking about OneDrive again. For OneDrive, it would be fine and dandy if WP devices were sold only in developed countries with internet access freely available anywhere. But this is not the case. These devices are sold in a variety of countries around the world. And in a significant number of these countries, most people don't have WiFi access outside their own homes, and mobile data is really expensive. OneDrive is almost unusable for those people, who're a significant portion of the WP customer base, besides using for small files like documents or presentations. Now don't get me wrong. OneDrive is implemented really well, and when it can be used, it's great. But just because you're content with that, don't assume everyone else can be. Some people need to actually carry around their files with them on their devices.
All in all, 8.1 is a great OS, and I've been personally loving it despite a few problems, but it still has room to grow. I don't understand why, as fans of WP, you wouldn't want it to improve and beat the likes of iOS and Android.