Having played four blademasters to pinn, and having fought many more than that, I have a number of suggestions as to what could be done with the blademaster class. Note: Not all of these suggestions are tone downs. Some of them would actually be beneficial to certain races.
Stances
Shadowdancer: This stance is fantastic, in my opinion. It's great for halflings (one of the three stances they should EVER use in combat), and makes for a great communer/caster killer. However, I suggest it does need some toning. I have not played a halfer blm since the changes, so I'm not sure if this has already been done. But I think the strength cap should be 23. This allows for an increase in strength, without adding an insane amount. As it is, a halfling in shadowdancer AUTOMATICALLY gets +12ish hitroll and +10ish damroll. That is, in my opinion, absurd.
Doomsinger: This stance is also good, in part because most people don't know what it does, and in part because of what it does. However, there are some problems with it. Even mastered, you still hit mostly grazes, with a high-damage attack every round or so, two or three times if you're REALLY lucky. A blademaster, on average, gets five attacks per round with a two-handed weapon. That means that they're doing only doing about sixty damage per round (assuming they hit one MUTILATE and four grazes). I think, with the progression of the stance, the probability to hit low damage should go down greatly. That would also solve the problem I'm going to mention later.
Deathweaver: Perfect. The equivalent of drunken stance, I really don't think it needs anything.
Ironarm: Eh. I don't know if it was always like it is now, or if it got toned up with the changes. However, I do know that I don't like it now. I don't like any stance that can, with no penalty to the blademaster, disarm noremove weapons AND knock them to the ground (so they can be picked up by your opponent). Easy fix? Make it so ironarm removes predict. The ironarm skill lags when it disarms, and does damage, so this shouldn't be hard to code in for JUST ironarm. That way, if you get disarmed, you have one rounded (after recovering from the lag) to pick up your weapon, and enter the command that the blademaster would have been predicting. However, you cannot say, bash, until after the blademaster has gotten to backpin/pinwheel, so they lose no potency. And the disarm thing should be fixed so that noremove weapons go to the inventory.
Kairishi: I have not used it since the changes, and I never see it used, so I really can't comment.
Bladestorm: I don't know what happened here. Did the haste effect get toned down? This is an extremely vulnerable stance for a blademaster to be in (lowers AC, and no lag protection), and I think that maybe it should be like monkey stance. Hits do less damage, but there are more of them and they hit more often. Maybe have it subtract 5-10ish damroll, but +5-10ish hitroll.
Skills
Scrolls: I think blademasters should get the scrolls skill. Just my honest opinion.
Counter/Twin Counter/Vigil: As it stands now, most classes have no way to open combat against a flying blademaster that won't result in them getting hit by a counter/twin counter. That means approximately 75-100 damage, for free, and afterward? The blademaster can just flee and go back to sleep or meditate, causing the counter to kick in again. My suggestions? Make vigil an activatable skill, usable only with two weapons. It should last for, say, one hour to start, and go up with proficiency. Then it should have a cooldown timer for twice its duration. Also, tone down the twin counter damage. Right now, twin counter actually does MORE damage than counter, half the time. And counter damage, in this instance, should rely on vigil's proficiency, not counter's proficiency. I've been hit for anything from LACERATES through DEMOLISHES through sanc AND protection by counter. Granted, the demos were with a vuln weapon, but that's still a bit much for something that has no penalty whatsoever for the blademaster.
Predict: I really have no suggestions for this skill, except for a couple of modifications of what knocks you out of it. I think the list needs to be expanded to include disarm. Also, as far as predicting is concerned, I think blademasters should be able to predict the "ADT" Syndicate skill, onslaught, disarm, weapon cleave, and haymaker (if it can't be predicted already).
Spellkiller: I really think this should be able to apply to communers, too. As it is right now, communers are the best in the game at attrition. They can easily outlast a blademaster's mana. And that's all a shaman/paladin has to do to win.
Snakespeed: The damage on this should be toned down. It should counter the spell, yes, but it should not be hitting a MUTILATE/LACERATE through sanctuary. When combined with counter damage, it leaves a mage opponent nothing but area spells to attack the blademaster with, and that's really just not fair.
Doublesheath: FFS, make the proficiency go up. You're killing my mastery list.
Onslaught: Backpin/Pinwheel - I think the Blademaster should only be able to pinwheel if they're dual wielding, much like a thief can only dual backstab/dual circle stab with two weapons. However, in that case, I think that the backpin damage needs to be toned up slightly, and the pinwheel damage toned down slightly, so they're even. Without sanctuary, they do fairly even damage. With it, backpin hits for a maim/decimate, and pinwheel hits for a MASSACRE/MANGLE. Make it so they meet in the middle, and both do LACERATES, so it's still a worthwhile skill.
Critical Strikes
Wrist: Give this a chance to make the opponent drop their weapon. This is an extremely underused critical strike, as is.
Spleen: Make the timer on the maledictive last for a shorter period of time. Two hours tops, I think.
Temple: Make the timer on this last longer. As it stands now, I believe it lasts one hour with a mastered critical strike. That means you have to intuitively know when your opponent is going to flee (which could be anytime between half and a quarter health), and use it. And even then, they can still catch a lucky tick, and escape.
Diaphragm: Lower the effect of this, VASTLY. This should be like a trip that goes through flight, in my mind. Sure, Communers/Mages can block it, but melees shouldn't get shafted on that account.
Solar Plexus: Increase the effect of this. A Blademaster SHOULD own their mastery race nine-tenths of the time, and this is scarcely better than the diaphragm strike, which makes no sense.
Races
Halfling, Slith, Feral, Elf, and Drow are all great. Dwarves and Duergars will be fine if the above Doomsinger change is made. As it stands now, Dwarves and Duergars do not have a reliable, good two-handed stance that they can make use of, limiting their effectiveness against melees. Gnomes... well, who would play a gnome blademaster? And finally, we come to Undead. Undead are the primary reason that I think spellkiller should also affect prayers. As it stands right now, undead just don't stand a chance against healers/clerics/paladins.