20-30 is pretty good i think in length. 30-40, not so bad either. But 1-20 DOES need more length, especially 1-10. Its really ridiculous how fast you go through those levels now and the gear for those levels is completely unnecessary now because you rank so fast. I'm approaching 40 now and it feels like a mountain already in front of me. Lots of people I know say it's simply "painful".

My interpretation that is not so much the SP to get to 50, but probably more the way we're still getting SP to get to 50. Grinding the same things, force abandoning leves to ensure a retry next reset, ect. It's not fun. If the content can't be made more fun, then it should be shortened perhaps so we can move on to ranking up something else sooner.