I'm mainly complaining because media playback was a key feature on the PS3 that actually led me to using my PS3 more than my 360. mainly because I found it easier to playback, and store, my media files on my PS3. You couldn't really store the files on the 360 ( had to read from a USB drive ), which it seems is also now the case with the X1.
So, since the PS3 had all those features, I fully expected the PS4 to easily have them, as well.
It would be like if the new iPhone 6 suddenly dropped key features that were present in the past models. You don't think Apple fans would be mad about that, especially when it's a relatively "basic" feature ( playing media files )? You don't think Apple fans would be mad if Apple revealed the iPhone 6 next week and said "We're going to make this the best damn phone in history. The primary focus will be on making phone calls. All other features will take a back seat."
At the end of the day, yes, I'm going to use my PS4 primarily to play games. that's what I bought it for. but, it would also be nice if I could use it for other things. Gaming consoles, like smartphones, have evolved to become multi purpose, multi function devices.
adding media playback may not have been an urgent priority for Sony, but now that the X1 has it, that kind of forces their hand to add it sooner rather than later.
cuz, right now, that is a feature the X1 can legit claim it offers that the PS4 doesn't. and I'm sure Sony wouldn't want that to continue for too long.
also, another reason, is that some games, like the WWE games, actually made use of the media files stored on your console to use as entrance theme music.
as of right now, it looks like that feature won't be in the new gen versions of WWE 2K15. so, in an instance like that, lacking media playback is actually affecting the gameplay experience to a certain extent.