I'd like to see a feature in Shotgun that allows an admin to login as another user without resetting their password. With the increasing levels of complicated permissions its sometimes really hard to debug a permissions related issue without logging in as that user.
Uncharted is experiencing this where we have complicated Shot, Asset, etc assignments to Vendors but the only way to verify a permissions issue is to login as them as see it first hand. This currently requires resetting their password which is a pain.