It seems as if this is not a question but a plea to Apple to allow the functionality. If you want to make suggestions ot apple, please use their feedback page, as nobody from apple is reading these forums for ideas:
You can install any new font which is in .ttf or .otf format on your iOS device running iOS 7 with AnyFont:
Afterwards these fonts are available system-wide in apps like Pages, Numbers or Keynote.
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<Edited by Host>