I'll still probably get a PS4 as that is the one that my mates have pre-ordered (and sunday nights would be pretty bare without getting thrashed by them playng online Grid 2). However:
PS3 games - very annoying, but at least that is something I can understand. New architecture, very difficult to make backwards compatible. They managed it for the PS3 ->PS2 games, but I guess things have got more complicated.
Bluetooth - WTF??? Why won't my bluetooth headset work? Have they gone out of the way to cripple it???
DLNA - I DONT WANT YOUR CRAPPY ONLINE SERVICE SONY! With your encoruagement (remember, Sony made a big play on the PS3 being a media hub) I made the PS3 the centre of my under-telly hub. I have music and films ripped to a server that my PS3 serves very nicely over my network to my sound system and TV. I could understand it if it was a feature that you were planning to put in later (like the PS3) as you con't quite get it done for launch day (like blu-ray films), but that doesn't seem to be the case.
Music - Really?? I have 2 boxes in my unit under the telly - Sky and PS3. I don't want to add one or two more (play CDs, stream DLNA). Why they hell have you removed this? Again if it was coming later as patch, fine. But to cripple it to force me to use your crappy online service is terrible.
I have a rasberry pi, and I've used it very successfully as a DLNA server but it makes hooking things up complicated (do I have enough HDMI ports, how do I rig the sound to make it easy to switch etc). I know there are solutions, but this is a real retrograde step. If my mates weren't getting a PS4, I think I'd go Xbox.