It seems (according to the King Follet discourse) that at the end of his short life Joseph Smith may have felt that the single most important element of his teaching - of the radical re-making of the what Christianity had become - was to restore the simple, concrete, literal, common sense and obvious understanding of God the Father - as He is revealed in the Bible.
Such things that God is a person, has a body (in whose image our own bodies are modelled), and more importantly has emotions - that God and Man are of the same basic kind or nature; and that despite that God and Man differ vastly (one might, using the word causally, say we differ 'infinitely') the difference between us is quantitative, and not a distinction of two utterly different orders of being.
It is like blinkers being removed!
Suddenly, the Bible's great promise that we are children of God, that He is our Father, that we are offered the chance - by the work of Jesus Christ - to become Christ's co-heirs (hence divine)... suddenly all this makes common-sense!
Suddenly we can speak the Lord's Prayer with comprehension and conviction; instead of...
Well, instead of beginning the very basics of Christian instruction or explanation by erecting a philosophical filter between us and the plain words - so that almost everything is re-interpreted to mean something other-than the obvious sense.
As an example, take the opening of Charles Williams's 1938 book He came down from Heaven in which he sets-about explicating the first phrase of the Lord's Prayer: "Our Father which art in Heaven".
One might have supposed that the prayer which Jesus taught us would be reasonably lucid; but immediately the philosophical abstractions are inserted between the words and our understanding (or perhaps I should say our 'understanding' - because to insist that abstract philosophical terms are the real truth is effectively to block understanding permanently and ineradicably).
Williams opens the commentary on the Lord's Prayer as follows; his words are in italics, my comments are in square brackets:
Its opening words undoubtedly imply a place in which "Our Father" exists, [instantly the basic address to God as our Father is problematized by surrounding the phrase with scare quotes] a spatial locality inhabited by God.
Against this continual suggestion so easily insinuated into minds already too much disposed to it, ['continual suggestion' implies that people are being misled, and 'insinuated' implies that this misleading is deliberately covert, and 'minds already disposed' implies that such minds are either tainted with evil or stupid in drawing such a conclusion.]
the great theological definitions of God [by contrast, to the wickedness, foolishness and dishonesty of simple understanding, the theological definitions are called 'great']
which forbid men to attribute to him any nature inhabiting place are less frequently found and less effectively imagined. They have to be remembered. [Here Williams starkly asserts that men are 'forbidden' to believe that God has a material body occupying a locality - it is therefore said to be compulsory for us to regard God as immaterial and unlocalized - despite the candid acknowledgment that these beliefs in the abstract properties of God are both unusual and in practice unimaginable - yet this unsuual and imaginable thing is what we 'have to' do!]
I could go on but it would be tedious and repetitive. Suffice to say that Williams is stating here something that over the centuries has been usual for intellectuals engaged in presenting Christianity in summary: which is to state Christianity through the lens of negative theology (the theology of denials, the listings of what God is not: such that He lacks body, parts or passions in the words of the Westminster Confession) and in terms of abstract terms such as: omnipresence (God being everywhere and unlocalizeds - as asserted above); omnipotence (God being able to accomplish anything and everything which can be accomplished); existing unchanging outside the universe, outside time; and God being divided into three persons yet also being one person - and all the rest of this complex, incomprehensible, abstract, intellectual stuff.
It was Joseph Smith's early and astonishing achievement to get past this vast and obstructive apparatus and remake theology on the basis of something close to a plain and commonsensical understanding of scripture.
Of course, he did a lot more than this, and Mormonism contains a lot more than this; but this was the most profound - and profoundly welcome - insight he provided: that Christianity remade on the basis of a commonsense understanding of God 1. is coherent; and 2. is still Christianity.
Joseph Smith rediscovered God as a person, as our Father; as someone sufficiently comprehensible thus knowable; and, even more, as someone with whom each of us could imaginably aspire to become a divine 'friend', a son or daughter (albeit at the end of a vastly prolonged incremental and accumulative process of spiritual progression, theosis, sanctification, divinization).