I should start off admitting I've never actually taken blademaster, but I think rushing straight to vampyre is the best strategy.
The only thing either trait does is give you something for killing a mob, blademaster gives you an extra turn and vampyre gives you health. Unfortunately the extra turn is only situationally useful where as the health is always useful. Worst yet, if you encounter a lone mob then blademaster does effectively nothing.
In terms of resources, time is clearly more abundant then health. You can take a near infinite number of turns to win if you want, but there is only a finite amount of damage that the power-ups generated can heal. I suppose one can argue there is only a finite amount of battle-time and blademaster gives you more of that, but I still feel that overall vampyre will heal more health then blademaster will save. Vampyre also gives you a resource you can keep and "spend" later (by taking damage), where as blademaster forces you to "spend" the resource immediately.
As for taking the third level of brute, I always take it after vampyre, but as the very next trait. As it's been pointed out, the third level of brute helps trigger berserk more often, but the difference doesn't feel noticeable enough to delay getting vampyre.