https://www.playeraudit.com/servers
don't click that. don't scroll down to character level and content level distributions. just don't do it.
over 85% of the content being played is sub 30. over 75% of the characters logged in are sub 30. this isn't a gut feeling. these are hard numbers.
you want the game to be balanced for the highest level of play at the hardest difficulty setting? where it will matter to 2 out of every 10 players logged in at any given time? i see, i see... tell me more about this "balance for the top first" plan. if you want to achieve class to class parity, do you start by looking at level 30? interesting. very interesting. when you are trying to balance gear, number and power of effects, accessibility, usefulness across class platforms, do you start at level 30? uh huh, uh huh... i think i'm starting to understand.
real game balance begins at level 30. nothing matters before that. real game balance precipitates fotm builds, forcing players to pick the winners the dev's have provided for us. no bad builds need apply. real game balance is demonstrated when a handful of top players running a handful of fotm builds dominate the hardest difficulty setting. bingo, it's DDO.