Not sure about the hard cap. We'll have a lvl 30 soft cap in the next patch, and, right now, you need more than 125 Million XP to reach level 50 (and that will drastically increase in the next patch). But yeah, if they actually spent countless hours trying to reach some high level, why putting a hard cap at level 30, or 35 ?
If a hard cap was needed, put it at 40. People wanting to advance their character spending nights on it would still be able to do it, with limits.