I heard a while back, in some update notes, that Davy Jones' Reach was no longer able to target and affect allies. That's exactly what was done; unlike the rest of the AoE powers in the game, we can't use the spell if an ally is standing in the middle of the 3x3 target area.
It's like this:
XXX XXX XXX
The red squares are enemies, and the blue square is Captain Stinker, someone's ostrich. You can't use Davy Jones' Reach on the whole group, just because there's a teammate in the center. You can't target nor affect your allies.
But when using Mojo Storm, you can target but not affect the ally. You can use the spell even if there's an ally standing in the middle of its radius, and you won't do anything to the ally.
When Davy Jones' Reach was "fixed", it prevented us from putting the center of the spell on allies' squares, worried that the spell would affect them.