I wish I could find these charts. I love me some statistics.
Anyway, other people sum it up very well. The sorcerer is just garbage. I particularly like to play support/spellcasters/etc but he has no presence. What he can do he isn't good at. He is not a good healer, his spells are garbage, and the purple sword is useless. It loses to everything. The beam instantly reveals your location which makes it much easier for people to use plasma, grenades, or run up and melee you. In fact, the sorcerer is pretty defenseless in most situations. He is easy to beat at range and in melee. His heal takes too long. One person can literally keep putting down the target you are trying to heal and slowly make their way to you and kill you. The corruption spell is so easy to remove and takes such a long time to build; not to mention the HoT from the apothecary makes you immune to this. Plus, ALL of his spells are channeling and they are prone to be bugged.

Bugs I found:

• Healing takes ammo, doesn't heal
• Healing doesn't take ammo, also doesn't heal.
• Healing sometimes won't give EXP if target is running.
• Switching to bolt pistol will sometimes bug all spells and also fix the spells sometimes.
• Corruption sometimes doesn't work and also tends to give 0 EXP.

All these factors makes an extremely broken and almost useless character. He needs more emphasis on Chaotic SPELLS that WORK.

TLDR: Sorcerer Sucks at his job.

Apothecary doesn't suffer from any of these things. Feel like being ranged dps, get a bolter. Melee, no problem. Chainword and Plasma pistol? Sure why not. Everything works for the Apothecary. He can do his job. The Sorcerer is just severely gimped.

Here is the data they released recently.
http://us8.campaign-archive1.com/?u=813aa425c2f4e16c135aee442&id=9adc86c0a5&e=380c1587b4

Hope it helps.

The stats seem a bit skewed, i.e how can the average number of kills across all players be greater than the average number of deaths, with suicides you'd think this would be reversed or at the least be the same number, unless suicides are counted as kills or x2 people are getting credited for a kill in some cases I guess.

Are you sure their low rate of being used isn't just because they're a magic-user in a sci-fi game?

It only counts as death if you bleed out. But it counts as kill if you down someone.

If the Aspiring Sorcerer was actually more magic based and had offensive spells like Doom Bolt/Warp Fire/etc. I would wager they would be one of the most popular classes on Chaos side.

A big draw for Chaos is the fact they have all that magic power at their disposal so no I don't see how them having magic powers in a sci fi game means anything. It's one the charms of WH:40k that they have an interesting mix of mysticism and technology.

Tons off people love their warpcraft in 40k. I would say they like it BECAUSE it's magic in a sci fi setting. Kind of like biotics in mass effect.

40k is typical fantasy in space, not a sci-fy.

Yes, especially because when we first did the votes for base classes they were the most popular.

Are you kidding? I wanted to main Sorcerer precisely because I wanted to kill people with magic. That's also the reason I don't play it now.

In fact back before it was actually implemented it was polled that aprox 1/4 of Chaos players wanted to play as a Sorcerer as their main. It's clearly not that they're magic, it's because they're a weak class in a shooter.