This has always been stumbling block for me as far as the EO Church goes. In fact, at one point in my life, this was the single reason for making me almost join the OO Church (never mind the problem of the Nature(s) of Christ).
St. Gregory Palamas says that the Uncreated Light is the energy of God, while drawing a distinction between this and the essence of God. Similarly, it is be the former that we are deified, the latter forever beyond us.
But how is this not di-theism? Does this mean that from all of eternity, there was this split within the Godhead? Or does this split exist only "economically" (i.e. is meaningful only within the context of man and his deification)?
To me, it sounds too muck like Neo-Platonism, with its never-ending series of demiurges, nouses, logoses, etc. which try to buffer God from his own creatures. As if God was some sort of whimp who can't stand the presence of His very own creation.