It should work like this:
You have to make nine choices, one for every 10 level starting from 10.
Every Stage has it's own theme, just like it is now.
Every Stage offers you to choose one of two possible talents.
One of those talents can allways be choosen by every spec of this class while the other is spec specific.
The Death Knight Tier 1 Talents are focussed around diseases. Here it could look like this
Class: Reduces your "Outbreak" cooldown to 30 seconds. Killing a target which grants exp or honour will reset the cooldown.
Blood: Your bloodboil spell will trigger pestilence to spread your diseases to surrounding targets.
Frost: Obliberate deals all of its bonus damage even with only one disease on the target.
Unholy: Wandering plaque: Gives your blood plaque ticks a chance to explode, dealing x damage to all enemys in range and applying blood plaque to all enemys hit by this effect. This effect can only proc once 4,5 seconds.
I hope you get the Idea.