Chilling Aura is just usefull without any condition, you dont need to actually make damage to get a benefit. (My shadow almost never gets thru War glads, 80% of all attacks are deflected but stil drains them solely with Chilling Aura)
Stil it should be balanced at that time ( it was a bit stronger some months ago)

Shadow Form is much more complicated, it depends on successful hits on the right type of armor.

Chilling Aura works with naked glads and equiped glads almost the same, thats why it looks overpowered.
Shadow Form should work very good with a fully equiped glad. (No real evidence here, never had a fully orange offensive Shadow) And the main issue with most offensive Shadows right now is the lack of heavy weapons used and/or some like "Dire Wolf" which uses whips but no entangle skill. Or some exotic guys like "Kullervo" with heavy weapons in both arms but poor equipment.

Nets are just very usefull right now. I tryed out a whip in the mainhand and it worked fine even both weapons shared the Entangle trigger >.<
But it should be very possible to replace the net with a whip and get almost the same results in terms of defensivly manipulating the opponent. A fist fighting Rager is much less intimidating as a rager with a net over him!

Whips are the way to go for those crazy inbetween builds and the same is true for offensive Shadow Form users.(in my opinion) Never saw one with whips and Entangle skill fighting in bloodgods.

The best way is to use both fighting styles in almost every fight, i did a howl BG season with only Shadowdance and it didn't work that good

Once Kullervo/Sarlesh are full orange they will be much more potent.

I don't see a good mixed shadow build, maybe drop "Shadow Form" for "Weak Spot" or "Cheap Shot" and use heavier weapons. Both skills are pretty good