I first came across the idea of a Positive (as well as a Negative) Christian theology in the writings of Charles Williams - he also called it Romantic Theology and the Via Affirmativa or the path of affirmation of images. The general idea was that Christian theology had typically been a path of negation, denial, asceticism, celibacy - but that there was also a (neglected) path focused on romantic love, art and poetry, richness of imagery etc. Williams regarded these as equal alternatives.
But it is hard to see how they could be equal, since they are so different - alternatives, yes, but in real life one or other of such vastly different paths is surely to be preferred; one or another must become the focus of societal aspiration and organization - one cannot aim both at being a celibate, solitary ascetic hermit or monk; and also at being a husband and father engaged with 'the world'.
Charles Williams knew (so far as I can find) nothing about Mormonism - and he would likely have found it to be boring or unpleasant if he had known anything - but Mormonism has for a long time been advocating and practicing something pretty close to Positive Theology: a Christian 'way' focused on marriage, family and engagement; and with no tradition of monasticism or the eremitic (reclusive) life.
Fundamentally I believe there are very different aspects of human psychology at work behind the positive and negative paths. The negative path aims at the relief of suffering, and the positive path at making life more fulfilling.
To feel the desire for the Christian negative path seems to me a desire to escape the sufferings of this world and live, instead, in a state of static bliss - absorbed in a permanent communion with God (who is, in essence, an abstract entity about which nothing positive may be asserted): doing nothing, simply being.
In the negative path, Love is seen as a sameness, a fusion of wills, the loss of barriers and all strangeness.
And there is no sex - indeed there are no sexes: maleness and femaleness are lost.
To desire the positive path is to wish that the best things in life be amplified and sustained - it also stems from the concern that static bliss would (sooner or later) become boring; and the conviction that the only thing which is not, ultimately, boring is actual, real, other-persons.
The dyadic goal of Mormon salvation can be seen in this light - the ultimate bliss is not the state of an individual soul in permanent communion with God, it is a man and woman in a permanent and divine Loving relationship at the centre of a network of loving relationships including God the Father and Jesus Christ (who are solid persons).
The difference between this version of the positive ideal and the negative ideal is profound - because in a permanent and eternal dyadic and sexual relationship between husband and wife, there would not be a desire for fusion and sameness but rather a delight in fundamental and complementary difference.
Sexual difference, and sexuality, both entail difference - a you and a me: not communion nor fusion nor loss of self nor consciousness. Instead a perpetual delight that 'we' are not the same, but 'fit together'. There needs to be the perpetual possibility of being delight-fully surprised; which means that there can never be full communion. Indeed if communion is full, it renders void the separateness and necessity of the dyad.
If a husband and wife become one, they stop being husband and wife.
There is indeed a desire for surprise, for open-ended possibilities. Once static bliss is put aside as a goal; it becomes essential that eternal life be interesting, rewarding, creative and (in some sense) progressive or evolutionary - changing, growing, developing without end-point or end. Otherwise - if life were static, or merely cyclical - it would become predictable and boring, and we would prefer a state of blissful loss of self.
It seems to me that Heaven must either be mostly like either the Negative or Positive ideal and that God would have a preference between these goals for Man - but I do not see why Heaven would have to be exclusively the one or the other.
So I see the Positive Way as primary, and God's first wish for us, and the basis upon which eternal life and Heaven are organized. But I see the Negative Way as an option available (on Earth and in Heaven) to those who - more than anything - wish to escape from suffering and hope to lose-them-selves in blissful communion with the divine.
Note added: Charles Williams descriptions of Positive Theology are at least difficult to understand, and probably fundamentally incoherent - this is because Positive Theology is metaphysically Pluralist - or at least implies this; while Charles Williams was very much a Monist who sought always to reduce apparent dichotomies (e.g. Good and evil) to unity.
If relationship is an ultimate goal and possibility, then there must be at least two irreducible entities to have the relationship - because if Man and Woman can be reduced to one, and Man with God can be reduced to one, then reality is One; and Positive Theology merely an indirect and off-route means to the same end as that which Negative Theology aims-at directly: viz oneness.
So Mormons - as pluralists - are the true Romantic theologians; and Charles Williams is fundamentally and ineradicably confused!