Gadwick has been officially spoiled so this obviously might be a wait for the FAQ situation. But it could also be upcoming errata situation so wanted to make sure it was seen.
Gadwick, the Wizeneds ability for drawing is a trigger and by 107.3f under the current rules he doesn't work.
Comparisons can be made to
Venarian Gold and
Endless Scream which both use different wordings to fix the issue.
If noone can comment yet I understand, just wanted to point it out. As I said could be a rule change/FAQ issue or could be errata.