I think some people are seriously overthinking this power.
The triggering action is "an enemy moves adjacent." An enemy moves adjacent, Dragonshield Tactics triggers. There's nothing there to suggest a Dragonshield must (or even can) wait until the move action is entirely complete before making the shift.
The fact that it's a reaction instead of an interrupt does not mean we should interpret the triggering action ("an enemy moves adjacent") differently. It just means that the Dragonshield Tactics power cannot prevent the triggering move from taking place.
The way people are interpeting this power is complicated, confusing, silly, and somewhat contrary to the role the Dragonshield is supposed to play. It's essentially a defender; it is not meant to be dancing away from blows, it's mainly supposed to be taking them on the chin.
The triggering action is "an enemy moves adjacent." An enemy moves adjacent, Dragonshield Tactics triggers. There's nothing there to suggest a Dragonshield must (or even can) wait until the move action is entirely complete before making the shift.
The fact that it's a reaction instead of an interrupt does not mean we should interpret the triggering action ("an enemy moves adjacent") differently. It just means that the Dragonshield Tactics power cannot prevent the triggering move from taking place.
The way people are interpeting this power is complicated, confusing, silly, and somewhat contrary to the role the Dragonshield is supposed to play. It's essentially a defender; it is not meant to be dancing away from blows, it's mainly supposed to be taking them on the chin.