It seems that many Christians are and have been focused on the problem of achieving salvation by faith and right choices during mortal life: this links-up with an understanding of Heaven as a reward for those who have achieved salvation - and Hell as the place of punishment for those who do not.
Mortal life is then seen as a battle to attain salvation and/ or to avoid damnation (the emphasis varies) - and a good life beyond death is the reward for good performance. From this perspective nothing much important 'happens' in Heaven - it is a state of being.
But if we instead take the view that Jesus won salvation as a gift for everyone, by his life and death - then salvation is there for us, and the primary condition is simply that we accept it.
Of course, accepting salvation entails more than merely saying 'yes, okay' - because salvation is into God's world and God's plan, and entails accepting and embracing these. And this is something that, apparently, some people - probably many people - do not want and will not accept.
If salvation is a gift to those who will accept it, then salvation is straightforward and secure (for those who want it); and the main purpose of mortal life is not salvation but theosis - the process of striving to become more God-like; or more exactly the voluntary process of becoming more God-like on the basis that we begin as partly divine (being children of God) and end-up as being brothers and sisters of Christ - of the same nature as him.
Heaven is the not a reward but the place where people who have chosen theosis continue to work on this - Heaven is a place of striving, of change, of work.
Hell, by contrast, is the place for people are are not aiming at theosis - people who are not trying to become more divine, more like Jesus Christ.
Which is the reward and which the punishment depends on what is wanted.
God was creator and has a plan for his creation - this plan includes creating possibilities for those who want-to 'join' God as a god; to become fully-divine sons and daughters of God - being able to 'work on' this goal, co-operatively and with love - partly during mortal life, but also necessarily after it.
By this account, God's main concern is theosis - so that men and women may choose to become divine, and may incrementally (and over a long timescale) achieve this by being born incarnated, dying and resurrecting; and also by learning from their experiences throughout.
Our primary choice is whether to join God's plan - or not. Hell is the place of nay-sayers. Not joining the plan may mean going-it-alone, or it may mean living among the others who rejected God's plan - and seeking what solutions and satisfactions that company may bring in a universe without meaning or purpose.
In sum, since the 'Mormon Restoration' of Christianity, and the change in understanding it brings; there has been a qualitative change in explaining the basic nature and purpose of Heaven and Hell.
(The extent to which Mormonism was a cause of these general changes in understanding Heaven and Hell, and to what extent it was a shared consequence of underlying spiritual causes, I don't know - something of both I expect.)
I don't think many Christians have fully 'taken on board' this change, aside from feeling a deepening dissatisfaction with the idea of Heaven and Hell as merely reward and punishment, and mortal life as merely a kind of qualifying exam.
But if (thanks to Christ) salvation is there for for the accepting, and on conditions no more onerous than repentance; then theosis is the main business of human existence - theosis in pre-mortal, mortal and post-mortal life - then the nature and purpose of Heaven and Hell are profoundly different.
Heaven and Hell are not states of being, but domains distinguished by the positive or negative purpose of those who choose them. Their 'state' is a consequence of this choice, and of the make-up of the populations that result from that choice.
Heaven is not a fixed state of being, but the place of mutual love where a particular purpose of divine destiny is being actively, voluntarily and joyfully pursued - and Hell is... well, all the rest.