[This 'ere is primar'ly fer Jonathan Prejean, but y'all a' we'come t' jone in too, Ah reckon.]
I’m unconvinced Western theology's view of divine simplicity has the decisive weight it allegedly has in the Catholicism-Orthodoxy debate. My fundamental objections to, or at least reservations about, Palamism are the following:
(1) It lacks dogmatic force because Palamite theology is a theologumenon. Without an ecumenical declaration in defense of it, it cannot have the weight it needs to have for various critics. As a corollary, I fail to see how the Orthodox could produce such an ecumenical decree in their current relationshsip with Rome.
(2) In conjunction with point (1), Rome seems remarkably open to allowing the essence-energies in its truly catholic dimensions. As a Catholic, I see no reason to make it a more divisive issue than the episcopacy teaches me to understand it. There really are Byzantine Catholics, and St. Thomas really does defend "uncreated operations" of God, honest. The simplicitly addressed in Florence must be understood as referring to the intrinsic simplicity, the pure self-sufficiency of the Godhead, apart from any extrinsic basis or motivation. Any undue conclusions drawn from those councils that actually do trap God within necessity should be corrected. But the doctrines themselves seem technically beyond reproach, particularly since they were undersigned by Orthodox at the time.
(3) What's necessary for the Thomist goose is necessary for the Palamite gander. The energies seem to me just as necessary in Palamism as creation allegedly is in Thomism. Certainly, creation is not God Himself in the way the energies are described to be God Himself. Nonetheless, one of the key points about the energies is that they are necessary to God's being. God is not God without them. Further, they allegedly free God from any (Thomistic) necessity based on His essence. On account of his "enhypostatic" energies, God is not bound by His own essence but can *freely* extend Himself in creation and in man. The Palamite claim is that Thomism forces God to create (or to redeem) since His action and will co-inhere in one absolutely simple essence.
The fundamental problem for Palamism is that the energies are, like creation and redemption, inherently exterior acts of God -- they are "God for us" -- yet they also derive directly from God’s pure essence. How then, after all, are they and their effects so free from the necessity of essence? Indeed, I’ve had a leading proponent of Palamism admit this is a huge bugbear of a problem, so decisive in fact that he says it would discredit all of Christian theology. That being the case (in his eyes) I think he and any other Palamist needs to cool his jets while the work of ecumenism continues this side of the eschaton.
(4) We truly know God in Christ, which also entails we know him in the manner of Christ (even if perhaps not in the same intensity). If Christ knew the essence of God, then we can too. If he did not know the essence of God, how can he be said to truly communicate God to us in the energies? Did Christ, as true man and true God, behold the divine essence? If not, what of his unity with the Father as the Second Person of the Trinity? If so, how could he, a human, know the unknowable essence of God? How could he, as God, be one with God without also, as man, being “swallowed” or nullified by that beatific vision (as I gather Palamists insist any mortal knowledge of the divine essence would bring about)? If Christ could and did know the divine essence, and if we are to be made like Christ, and if we are said to possess his very mind, and, one day, if we are to know God as we are known by him (in works, energies and essence), then what remains of Palamism?
Now, having said all this, let me hasten to add I highly respect the fundamental aims of Palamism. I admire Palamas's genius and piety. I greatly admire the basis of Palamism being in PRAYER. I also greatly appreciate the holistic emphasis of hesychasm, neptic piety and theosis. I am, in fact, drawn by the heart to the Byzantine view of salvation, even in spite of my intellectual reservations. My objections are against the supposed "one shot, one kill" nature of Palamism vis a vis ecumenism, not against its obvious merits. I look with awe on the light of the East, and I see Palamism as one of the brightest gems glistening in that _orientalum lumen_. My point, really quite modest, is that light, whether from the West or the East, merges with light, and that the valid differences in the Church must be defended against simplistic triumphalism.
Peace be with you and please forgive any triumphalism or condescension on my part, in this post or otherwise.
 Cf. e.g. ST III.Q9.1a.
 The divide being forced between God’s essence and his energies – let us say between his will and his work – is all too reminiscent of Islamic theology, wherein Allah has an inscrutable volitional essence which is quite possibly (and sometimes certainly) foreign to any of his manifested acts. Because Allah's essence is pure and inaccessible, and because, therefore, all we have is his providence within our mode of being, then Allah may or not really be what revelation shows him to be. In Islam, the providential "energies" of Allah are effectively one God (call him "Allah for us"), while the true essence of Allah is another god ("Allah for Allah"). And in Palamism? How do I face "God for us" and "God for God"?
 Cf. John 5:19-20, 8:38, 2 Corinthians 2:16, 1 John 3:2-3, etc.
 I'm sure to many readers my anti-triumphalism is the bitterest of ironies, coming as it does from a papist, but oh well.