Each of us can look at this creation and find ourselves, stories mirroring our realities. MB itself acknowledges the same when it says - yadihAsti tadanyatra yannEhAsti na tat kvacit (Adi Parva: 56:33;) - that which exists in this exists elsewhere too, but that which doesn't exist in this does not exist anywhere else. AK Ramanuja says about MB that it is a tradition, not a literary or textual creation alone. And in many ways it has grown into a multi faceted creation that is so intrinsic to many fronts of Indian life - science, theology, politics, philosophy, literature, art, cinema, novel etc.
Mahabharata is quite different from the other large Indian epic of Ramayana on multiple levels. While Ramayana is a straight forward linear story, MB is multi pronged, going in different directions without a clear moral lesson. In Ramayana, what is just and unjust is clear. Rama is just, Ravana is unjust. The just wins in battle against unjust.
In Mahabharata, justice is no one's monopoly. (It itself says, dharmasya tatvam nihitham guhayam - the truth about what is right is hidden deep in the caves). Ramayana is a fight of just Aryans against people who are not part of their "clan" / societies - against a king in a different country, leading to death of that country men, tribals with monkey and bear totems - none of whom are from Ayodhya (the country ruled by Rama). MB is complex because there the fight is among relatives - within a country, within even a house. Vast majority of death also happens among Kshatriyas, within Kuru clan.
Ramayana is triumphant, celebrates victory. MB is tragic with no final, lasting victory. There is nothing to celebrate.
Ramayana is affirmative - it is clear cut in what it wants to convey (definition of maryada purushotham, his embodiment Rama, his way of ensuring justice). MB is interrogative forever asking questions of readers and forcing them to debate answers and arrive at own conclusions.
Ramayana celebrates the embodiment of a perfect man, Rama. No human in MB is an embodiment perfection, including the future godhead Krishna.
Ofcourse there is no mention of MB in Ramayana (Since Ramayana supposedly happens in Treta Yuga, before the yuga in which MB happens). In MB Ramayana is being retold, for the benefit of Yudhishtir during Vana Parva. The context of Rama in MB is not as embodiment of human perfection but as an unlucky king who lost his all and had to spend time in forest. When Yudhishtir during his days of forest dwelling after having lost the gamble (and through that his kingdom, wife and brothers) to Kauravas, asks sages - is there anyone across Yugas who is as unlucky as me? An embodiment of the pinnacle of human misery.