The Neo Platonists considered that the divine was perfect and unchangeable, for change implied that the divine was not perfect (on the basis that change implied something became 'better' or 'worse'. Better would imply that something was not perfect before, and 'worse' obviously is moving away from perfection also). I don't accept the notion that change must involve any value judgement of 'better' or 'worse' than the previous state of affairs. For example is liquid water 'better or worse' than ice? This is surely some category error...'better and worse' are value judgements.
Nevertheless there is a further problem with the notion that the divine is perfect and therefore change is not necessary and the divine is 'complete'. There is nothing for the divine to do. Creativity cannot have an end or purpose that is good in itself. If the supreme good exists from all eternity then any amount of creativity and action does not add to the sum of all good. I find such a notion repellant, because I believe to create, even to simply be, is a greater good than non existence. One might state there are states of being of extreme suffering where non existence is preferred. However while there are some states of being that don't involve extreme suffering, I cannot see how overall being is not more good than non being. Indeed if there was only non being there could be no good at all. So the concepts of good and being seem intertwined in a way non being and good are not.
So I think we have a 'reason' for the universe, indeed existence, namely, for the sake of good. We might go further and notice that even pain and suffering and the overcoming and transformation and liberation from pain and suffering produce new forms of good: courage, loyalty, wisdom. The process of universal creativity tends to good and to the overcoming of evils, which is also good.
Where does this leave divinity? Is the divine complete and perfect? Clearly if the universe is an unfinished process toward greater good, then the divine is not in its essence the supreme good or perfect. We might say though that the divine is seeking or tending toward the supreme good in all things. We arrive then at a point of confirming a basic notion of process theology. We also accept the notion it seems that creativity is part of the divine nature and eternally so. This does not necessarily mean that creativity extends eternally in time I suspect. But the universe, which contains all time from a human point of view, is the manifestation of the divine. And we are not just like waves on the ocean who's nature might appear to be futile. There is a development within the universe. And I suspect the evolution of intelligent conscious beings is not an accidental and chance phenomenon of development, though as such sentience need not be the 'purpose' of the universe. Consciousness and intelligence does give more opportunity for good, in particular the ability of creatures to reflect upon the universe, to make the value judgement 'this is good' is surely a great good in itself.
What I don't want to return to though is the anthropomorphic notion that the divinity is a big self that is making the universe by its best efforts. A deity which is simply a very big and powerful self is a conscious manipulator of the objects in the universe. Creativity does not necessarily imply a deliberative mind or plan. One might side with the naturalists to see creativity as our word for a general tendency for an increase in multiplicity of forms, and their complexity as a 'law of nature'. If there is a cosmic consciousness, even if this is simply a knowing awareness of itself, an interiority to the whole process of the universe, we are probably cut off from it by the fact and particularlity of our existence. The finite cannot grasp the infinite anymore than one could capture the ocean by dipping a thimble in the sea. Equally the infinite, the ground of being cannot operate as a supreme actor in the particular facts of existence (by analogy my mind cannot encompass the celluar events within my body - I cannot attain a cell's eye view of things, and indeed I cannot through my mind do microsurgery or reorganise my organs and tissues.)