Ok so analysis:
So looking at Papi's first graph, there are too many warriors at all levels compared to other classes. This shows people genuinely like warriors the most. If they just didn't change their class when they started and didn't like it they would stop playing the warrior. But it doesn't look like they do.
There are not enough mages and druids total in the game.
Rogues and Rangers look like they each have a good share of 1/5 of the whole population.
Now looking at my graph, it looks like people don't feel an incentive (good cost to benefit ratio) to level their mages. People have leveled the druids they make heavily. People also have leveled their rogues heavily (or just stopped makeing new ones, which is unlikely). Rangers and warriors are average across the board which means people feel an average interest in leveling them.
Which brings us back to this point: all other classes are better to have than a mage.
Warrior: It's alright to level, solo easily.
Benifits: Tanking.
Rouge: Also good to level, solo easily.
Benifits: DPS
Druid: Pain in the ... To level, preferably group leveling
Benefits: Healing
Ranger: Again, alright to level, people solo level it easily.
Benefits: alright DPS, alright heal. All rounder class.
Mage: pain in the ... To level, what with energy costs and regen.
Benefits: Cloak, Energy healer.
Now,
Warrior-You want to level that warrior because of the ability to tank. Having a good tank means being able to kill bosses easier
Rouge-you want to level it because of the DPS it offers. Means you can kill mobs faster and keep the kill to your group.
Druid-even though it's tough to level, the rewards are sweet. Immense heals and buffs make it worth the while.
Ranger-now I'm not familiar with this class. But from the rangers I've seen, their light heal is amazing, they dodge often, they hit hard. So again, all rounder class
Mage-it's tough to level...is it worthwhile? I'm not entirely sure anymore. I mean granted: the cloak is nice. And the sacrifice is useful, but why would I spend my time on a mage when I could use it on a rouge.
Summary
In the end, a Mage isn't entirely needed. We're not relied upon.
Take this for an example:
Sadly, i was banned from my clan. Now I really wanted back in and after discussion with a friend, she told me I should go back to my warrior instead of leveling my Mage. I asked her why, and she said warrior's can tank. Mage's aren't needed.
So unhappily I go.
Sooo yeah.