Speed up the Later Levels you Cowards

Level EXP required should follow an inverse exponential curve.  I'm not sure if this is a universally held opinion but I think the first few levels are by far the most fun. The later levels are when the system balance and math start to show (cough 4th edition) and anyway the player goals or story if you have one should be heading towards a conclusion. So as a first pass I would keep the exp requirements for 5th edition flat over level 8, and rely on the increase in EXP from higher level monsters and encounters to speed things up.