Dust to Dust (Soulbinder) does not function

caexar

It grants no AP whenever souls sparks heal you and only grant a small amount (like2%) upon the end of combat instead (when the soul sparks time out)

tyrtallow

You should check the wording on it more carefully. It's only at the end of combat that sparks actually heal you (check your class mechanics). Other times, they grant you passive lifesteal (they're not actually healing you, just increasing your lifesteal) and while feats like Borrowed Time give you extra regen based on how many sparks you have, the sparks themselves aren't actually healing you.

Essentially this is mainly a solo/PvP feat, ideal for situations where you are constantly entering/exiting/disengaging from combat AND taking damage. To make it work in group PvE you must be able to generate sparks and end fights very quickly and you must be able to receive damage (and stay at comfortably low HP up until the end of combat, so the sparks actually heal you/replenish your AP by a significant amount).

tyrtallow

Update on this from preview. It no longer seems to matter if the sparks heal you or not, you get around ~5% or so AP if you have 30 sparks when combat ends.