I haven't decided on tiers for them. Aside from the heroics they could be arranged in any manner that seems appropriate. These are just a few ideas, more could be added.
spider's web (q): Shock web has higher slow and roots enemies if they stand there for too long.
tremor sense (q): Much longer range, puts a slight ping if someone steps in it (wouldn't show what triggered it)
Tiger Strike (w): Replaces side effects with an area version of the damage/stun which would be weaker. Main effect would be stronger and would gain power based on charges.
Claws of ice (w): Always triggers chaos ice bolt regardless of charges
Claws of fire (w): Always triggers meteor regardless of charges
Claws of lightning (w): Always triggers chain lightning regardless of charges.
These 3 would all be in the same tier
Cobra Strike (w): Gains life when triggered based on charges.
Cloak and Dagger (e): Gains bonus damage on attack first and when attacks or after 1 seconds cloaks
Blinding Cloud (e): Releases a cloud when cloaks that lowers enemy vision range.
Smoke and Fire (e): When cloaks drops a wake of fire sentry that fires off 3 waves of fire for light damage each.
Back up Plan (r1): If you die while the shadow master is alive you switch places with it and gain % of max health equal to the % of max health that the shadow master had. The shadow master also gains additional damage.
Pursuit (r2): When you flip the target you dash to the targets landing location and deal x% increased damage to the target.
Heroes of the Storm Build Guides
Momentum (trait): Gains x% move speed for each charge
Shock Field (q): Attaches shock web to self or enemy
Blink (e): Can target an enemy when uses cloak of shadows to teleport to them in addition to other effects
Lingering Fumes (e): Increases duration by 2 seconds.
Some of the cross hero talents