But by the same token, that make TWF work well with Reckless Swings.
So, here's the way I always thought of it... Two-Weapon fighting (without the talent) is essentially 2 actions that cannot be separated.
Two-Weapon Fighting (with the talent) is treated as two actions in order to keep consistency, but I also look at it as a single (2-action) Maneuver with a speed cost of +2 (0). As such, in my mind, you can take incidental movement once during the course of the TWF maneuver. (Mind you, this is my interpretation and not official.)
Spinning Strikes is a maneuver which improves upon the Talent version of TWF. And it explicitly allows for an additional 5' of movement between attacks, for a grand total of 15' of potential incidental movement.
If official word comes down, I'd be very interested, since my primary PC is a two-weapon fighter.
Scott