While gish animist is looking sweet, this feat is not. Witness of ancient Battles, the would-be premier user of this feat, cannot use it properly most of the time. Similar feats in other casters kits work to varying degrees of success because striking does not lock them out of what they want to do most turns, casting a 2 action spell.
Meanwhile, an Animist wants to use Embodiment of Battle before making any strike, leaving them with no room to activate Apparition's Enhancement outside of the very first turn (unless they want to use a 1 action sloted spell slot, but that is hardly sustainable).
What I would do is make it so Apparition Enhancement can also be applied when sustaining a spell. This would most likely warrant some changes to Grudge Strike (which to be fair, already needs some changes, IMO. With this change it would be a bit too good when you get it but it would still go down in value fast as you level) so Apparition Enhancement is factored in the damage this feat does.
This would make the feat way more interesting for Animists that don't have the Witness of Ancient Battles Apparition. The turns I picture an animist wanting to strike with a weapon are those they need to sustain their focus spell and also do some other 1 action activity like opening a door or drinking a potion. 1d6 is not enough to stop casting and start striking, but it is a good consolation prize.