If you don't like them that's fine, but your stated reason for disliking them as boring masses of element is contradicted by the PS Inner Planes and PC MC III.
Not really railing against you, but it just reminds me of the designers bitching about "How can you breathe in the City of Brass" and ignoring the mention of Air Pockets in the FIRST edition MotP.
So I'm saying that after listening to Hip Hop once and not enjoying the experience, I don't find it necessary to listen to a hundred more hours of the stuff to justify my preference.
As stated (Third Time) the existance of the Big Four (Fire, Water, Air, and Earth) are fine as iconic representations. One can even envisions "oozy" sections of Earth (if you really HAVE to) There can be a hell of a lot of variation within a single mass of element without making para, pseudo, quasi planes.
That said, friction makes not just heat, but stories. Stories are conflict and it's easier if big slabs of reality smack against one another instead of just sitting in one place. Rocky Road is a more exciting flavor then a big jug of vanilla. The PCs, needless to say, are the crunchy bits.
This is not (NOT) to say that there isn't enough material in PS canon with the elements seperate to make good stories, but it certainly makes it easier with them smacking around.