we have maximized how a phone should look like. you can have round corners like galaxy series or you can have straight edges like xperia z or iphone 5. other than that, this is what phones will look like for a loong time now. until they are replaced by see through glass phones.
hardware keep progressing. more cores, faster cpus, more ram. that is what separates new phones from old phones.
the different os systems have also reached a dead end in terms of how to use a phone. its all optimized almost to the full.
what this means is that iphone was the overall wow phone, everything else from there is kinda meh because we have now seen it all. hence why people complain about the galaxy s4 didnt wow them and why iphone 5 was nothing but a upgraded iphone 4.
its sad but it is what it is