On a discussion board devoted to Mormon apologetics a non-Mormon wrote about the progressive nature of the Mormon God. He quoted the ever-so-blunt Hunter and Widtsoe:
“Yet, if we accept the great law of eternal progression, we must accept the fact that there was a time when Deity (God) was much less powerful than He is today. Then how did He become glorified and exalted and attain His present status of godhood? In the first place, aeons ago God undoubtedly took advantage of every opportunity to learn the laws of truth and as He became acquainted with each new verity He righteously obeyed it.” – Milton R. Hunter, The Gospel Through the Ages, p. 114
“Therefore, if the law of progression be accepted, God must have been engaged from the beginning, and must now be engaged in progressive development, and infinite as God is, he must have been less powerful in the past than he is today.” – John A. Widtsoe, A Rational Theology As Taught by The Church of Jesus Christ of Latter-Day Saints, 7th ed, p. 24
Appealing to the Bible (Malachi 3:6; James 1:17) and early Mormon passages in the Book of Mormon (Moroni 8:18; Mormon 9:19; 3 Nephi 24; Moroni 7:22), the non-Mormon noted that even Mormon scripture seems to refute the notion of a progressive God. God is eternal, never has changed, and is the same yesterday, today, and forever.
The immediate response struck me as frustrating and yet insightful. I have seen a few ways that Mormons speak of the unchangeableness of God, of him being the same yesterday, today, and forever. Was God always fully God? Yes, they say. But I plead with anyone who interacts with Mormons: dig, probe, and examine. Do not take answers at face-value. Surely, you may say, surely if such important language is used in a significantly different way than commonly understood, surely you will be informed of the shift in meaning. Nay, I say, nay. When you dialog with Mormons—particularly with Mormonism’s defenders and representatives (official and unofficial)—you cannot assume that your interlocutor has a passion for honesty and clarification. Hope for the best, but prepare for the worst. When it comes to religious dialog, you cannot assume a Mormon shares the same ethical approach to language.
Yes, some expound when pressed, since, although he progressed to fullness, God was always fully God in species, therefore God was eternally, “fully God.” Nevermind that, in this line of thinking, you can be fully of the God-species and yet not necessarily know all things and have all power.
Yes, others will say, since God always existed (regardless of whether he had the fullness of what attributes most understand “God” to have), God was eternally “God.”
Yes, others will say, since “always” refers to this particular space-time continuum, God was “always” God.
Yes, others will say, since “always” refers to the range of time that begins at the formation of this particular world, God was “always” God.
Yes, others will say, since “God” refers to a variety of states of being, God was always “God.”
This particular Mormon replied:
“If God is infinite (which I believe means existing outside time) and also progressing then he has for all time been at his most powerful. Put another way if I am in the future exalted I will also be God yesterday, today, and forever in time extending in all directions infinitely.”
We can at one level sympathize with the Mormon plight over language, since they have dug themselves into an awfully deep hole. Having embraced post-BofM works as canon, and having embraced some important extrapolations of extra-canonical theological traditions in Mormonism (fostered by institutional leaders), they have quite the task. They must anachronistically retrofit pre-Nauvoo language with post-Nauvoo theology. Meaning has significantly changed. And by “change” I do not mean merely “expand” or “develop,” but rather negate and controvert the previous meaning. What is now relative must be somehow described in absolutist terms. Unfortunately, very few Mormons seem intent on seriously taking the advice of LDS philosopher Kent E. Robson:
“Mormons who are attracted to terms of absolutism should carefully consider what else they may unintentionally be embracing. They should consistently renounce such attributes or clearly distinguish between Mormon usage and traditional Christian usage.” 
Carl Mosser and Paul Owen, in their review of How Wide the Divide, write:
“We do not deny that Latter-day Saints describe God with the various omni terms (omniscient, omnipotent, omnipresent, etc.). But we feel that in Latter-day Saint terminology the meaning is so far removed from standard usage that it serves only to miscommunicate. The simple use of a term does not entitle one to all the privileges of that term, and no one has the right to redefine a word idiosyncratically. For example, what Latter-day Saints such as Robinson refer to as ‘omnipresent’ would probably be more accurately described as ‘omni-influential’ (compare D&C 88:12—13, 41). What he terms omniscient as ‘omni-aware.’ A God having influence everywhere is not the same as one having personal presence everywhere. Similarly, a God who has no false beliefs about the past and present and future is not the same as one who has knowledge of all things past, present, and even future. Further, an omniscient Being does not just possess the most knowledge, he possesses all possible knowledge—if it can possibly be known he knows it and always has. Likewise, a most powerful deity is not equivalent to an all-powerful or omnipotent deity. Having more power than any other being simply is not the same as having all power. We might also add that a deity without flaws and imperfections is not the same as a deity possessing all perfections.” 
Will Mormons strive hard to avoid using naked language that “serves only to miscommunicate”? The task is not easy. To do so, a Mormon must kick against the pricks of the strong inclination in Mormonism to use traditional Christian and biblical language in an unqualified manner. “Creedalists” are scorned for using non-biblical language. Doing so is often interpreted as prima facie evidence of being unbiblical.
As for me and my house, we will be proud of our Christian heritage. Christians have, at crucial points in history, risen to the occasion of using culturally sensitive, extra-scriptural language to clarify scriptural teachings. And while we must always be on guard to avoid retrofitting older biblical language with newer biblical revelatory teachings, and biblical language with unbiblical teachings, we have the advantage of a unified canon and a tradition that values the clarifying use of extra-biblical language. That makes our task a lot easier.
The heart of the problem of dishonesty with others is first not being honest with ourselves. Persistent incoherence within one’s own worldview and linguistic framework inevitably spills over into prevarication with other people. Ultimately, my Mormon friends, I believe that the most honest thing you can do is abandon the parts of your theology that do not cohere with older written revelation. Only then will you be able to be most honest with yourselves, and consequently, more honest with others.
 “Omnipotence, Omnipresence, and Omniscience in Mormon Theology,” in Line upon Line, 70, 74. Quoted in Mosser and Owen’s review.