Hrhr, just realised how badly abusable the Thief is with the charging rules:
L6: Human, Thief
20 Dex
-- Gritty Sergeant Background: Rapier prof, +1 init
-- Feats: Light Blade Expertise, Surprising Charge, Backstaber, Nimble Blade, Mounted Combat
-- Items: L7 Dire Boar (yes folks, you have to pay for that thing), L6 Horned Helmet, L5 Vanguard Rapier +1, GP Bracers of Mighty Striking
Because my mount is my ally, I can use Tactical Trick all day and hence get my distance to charge as well as gaining CA for it.
To-Hit: 3 lvl + 5 dex + 3 prof + 1 enh + 1 exp + 3 CA + 1 charge + 1 WT = +18 vs AC 20 = 5% miss // 90% hit // 5% crit
Damage: 5 dex + 2 finesse + 1 exp + 1 enh + 2d8 rapier + 1d8 vanguard + 1d6 HH + 2 item + 2d8 SA [+ 1d8 crit] = 37 normal // 61.5 crit
=> 0.9 * 37 + 0.05 * 61.5 + 0.95 * (0.6 * 20 + 0.05 * 29) = 49.15 DPR
Easily supposed L20 DPR at L6 without any shenangians, on a perfectly playable build and completely self reliant. Let's say I'm pleased.
If I have a way to gain CA by other means (charing into a flank, target dazed, ...) this becomes even meaner. I then use Unbalancing Trick to gain the distance, and as I knock prone on my hit, my mount deals even more damage.
=> 0.9 * 37 + 0.05 * 61.5 + 0.95 * (0.7 * 24 + 0.05 * 34) = 54.61 DPR with CA
And as long as my mount hits (62% without / 72% with CA like after winning init) I can charge again with an AP. => ~106 DPR on a usual AP nova round using my two Backstabs, without any support needed. Now who said Essential classes couldn't nova ?

Oh, and the guy still makes a great weapon to be wielded by a Warlord or the like...
PS: Numbers look correct, Lej. You still rely on gaining CA by your allies and possibly taking OAs to get your charge, though.