This is likely to be a huge powerup, which Druids most certainly do not need. The shapshifting variant is normally somewhat weaker than the standard wild shaping, particularly with the fact that Natural Spell doesn't work with it. But psychic warrior powers will buff them up like mad even if only manifested before shapeshifting.
I'd worry about how high their AC, damage output, DR, and healing (maybe) would get, since it's better than what a Druid could normally get with their spells. Sure, they lose out on summoning and blasting, but they just focus all that power on their melee attacks rather than wasting turns on less efficient use.
Playtest it first. Psionic druid alongside normal druid, at a few different levels.