Nope, you're still implying we can just pick one format and use it, we can't VOIP apps frequently use lower rates and fewer bits per sample. Some people WILL want their system to do 7.1@96KHz and there's no real reason to stop them. Once you do all the other stuff that GStreamer and pulseaudio have to do ANYWAY just to support common use cases you might as well support all the other stuff.
You CAN'T just say 'all audio is email@example.comKHz' because it simply is not the case, 48KHz audio exists, as does 24 bit audio, some people by expensive sound cards to get these sorts of things, and you want to tell them they can't have it?
All I was objecting too is the first bit.
Getting to the rest of your post:
Of COURSE nobody expects their mobile phone to spit out 24bit 192KHz 7.1 channel audio, but some people DO expect it from their desktops, GStreamer is used it a very wide variety of places, and some of them need things your phone doesn't, some of them need things you don't ever need, but that's not a reason for GStreamer to not support them.
Certainly 32 bit float is the most (more in fact) sample resolution you'll ever need in a storage format... but GStreamer is sometimes used in a processing pipeline so it MAY at some point have a use for doubles... probably not though.
ORC is a perfectly reasonable thing to use for a simple volume scaler, especially on something like a mobile phone where CPU time might be at a premium.
I think part of the redesign was to make the format negotiation better and more automatic, however, avoiding conversions is always a good idea (hey large chunks of pulseaudio code are dedicated to doing as few conversions as possible, because of phones and embedded stuff, and even on a desktop rate conversions add error every time you do one since the bandlimiter isn't perfect so it introduces aliasing and noise every time it's run, good ones don't introduce much, but they are expensive to compute even on a desktop)