The draenei are a fascinating people to me. Their ability to forgive is terrifying, in a way. This is a people that have seen the majority of their own kind become the stuff of nightmares - a people who have been hunted throughout time and space for over twenty five thousand years by these same fallen former kind, now transformed into demons by their willing adherence to the unthinkable, and it has changed the way they view everything. The draenei are willing to give people who have slaughtered them the benefit of the doubt, and manage to keep their hearts clear (for the most part) of feelings of vengeance and reprisal. The draenei leader Velen went so far as to help the blood elves who had kidnapped and drained the life out of his friend, the naaru M'uru, even through blood elves had stolen Tempest Keep and caused the draenei to crashland on Azeroth in the first place.
We know a reasonable amount about the draenei - we know they come from Argus, that they are refugees, those that chose to heed Velen's warnings and abandon their world before Sargeras could ensnare them in his web of lies and corruption. We know that they've fled the advance of the Legion for that aforementioned two hundred and fifty centuries. What we don't know is how it all went down. What worlds did they arrive on and settle only to have to flee again? Keep in mind that Draenor, the world they named, was only their home for roughly two hundred years out of that vast period of time.
To put it into perspective, Tyrande, Malfurion and the other until-recently immortal night elves, the ones who have lived from the time of the Sundering, are less than half the age of some draenei. Jessera of Mac'Aree, for instance, was fifteen thousand years old at least and had been wandering the cosmos for that long when the Sundering occurred. Not only are the draenei seemingly functionally immortal (they can die, but they do not seem to succumb to old age, or if they do, they have a means to lengthen their lifespans) but they've spent most of that deep time traveling from world to world... and we know almost nothing about that period of their history.
The draenei who have joined the Alliance and taken part in its factional struggles are survivors of the destruction of their last refuge and the near-annihilation of their people. For an ageless race, the loss of so many is terrifying in its desolation, for each death costs your people a resource thousands of years in the making. But what is hardest to realize is that it has colored our perception of the draenei and their culture - we only know them as the beleaguered, bedraggled few, the last desperate remnant of that greater society that endured the flight from Argus and the pursuit of the Legion for those twenty five millennia. In essence, what we have now is a society that has had to change, and change radically in some ways - has had to embrace a ruthlessness not seen before. The Velen we encounter in Rise of the Horde walks into the very hands of his persecutors to attempt to bring peace between orc and draenei. The Velen we first encounter on Azuremyst Isle is still willing to make that kind of decision, but he is also willing to instruct a draenei hero to kill every single blood elf that followed them to Azuremyst and Bloodmyst - mercy is an option, but now, the Prophet is willing to countenance another option. He's willing and able to order the extermination of his people's enemies.
It's understandable that this change would occur - not only was the near destruction of the draenei terribly thorough - most of them dead, many of the survivors twisted by demonic fel magics into broken or lost ones - but it was also terribly recent by draenei standards. Again, this is a culture that managed to survive and escape the Legion for longer than recorded history on Azeroth. The genocide unleashed upon them by the orcs took place within thirty-five years. That's an eyeblink in draenei terms.
The militant air of the modern draenei of Azeroth - the vindicators who were willing and capable of using force against unarmed human refugees who tried to push past them to Velen, as an example - comes from their having survived this horrendous experience. In many ways, the draenei of Azeroth are haunting by a racial survivor's guilt that manifests as a dichotomy - they honor Velen and his teachings gleaned in part from his exposure to the naaru and in part from his visions, but they've seen, experienced, lived that these teachings can't always save them. They haven't lost their capacity for forgiveness and tolerance - the lesson that in any heart can lurk evil applies to them as well as anyone else, they have the Legion's eredar to serve as examples of that. But they aren't willing to risk extermination for those ideals.
Warlords of Draenor can show us what the draenei were like before that, essentially. Furthermore, it can show us the clash between the defensively-minded draenei who haven't yet experienced the total annihilation of their culture and the more aggressively minded draenei who come through the new portal to a Draenor that is not the one they fled. With characters like Maraad making the trip, we have the potential to have a clash never before seen in draenei culture - that between the original culture of the exiles from Argus and that of its survivors.
Another element of modern draenei culture that should, at some point, be addressed is its paranoia about itself and its own people being corrupted. The time spent fleeing from the Legion seems to have bred into the people a deep suspicion of their own purity and ability to make their own moral decisions without the Holy Light thrumming away inside their heads, perhaps fed over thousands of years by repeated efforts from eredar agents of Kil'jaeden's to infiltrate their society. It's even possible that some of the draenei who originally fled Argus with Velen were plants, or changed their minds later, helping to exacerbate this suspicion. It can be most easily seen in the way the draenei, who are so often painted in glowing idealized terms, react to broken and lost ones. The loss of the connection to the Light was viewed not as a curse inflicted by their enemies but rather as a moral failing and worse, as one that might be infectious - heroes like Nobundo and Akama were effectively driven out of draenei society and into their own enclaves, exiled from the exiles.
I view this as a manifestation of the knowledge all draenei have of how close the line they walk between corruption and purity is. After all, the majority of the eredar race fell into a corruption far more extensive than that of the blood curse - while orcs became demonically tainted by the warlock magic and the blood of Mannoroth, the eredar walked willingly to their degradation and servitude to the fallen Titan. Having spent so long fleeing this choice, it's understandable albeit regrettable that the draenei failed to give their cursed brothers and sisters the acceptance and support they should have by their own cultural normals. It's ironic and regrettable that the draenei have shown more willingness to forgive and reconcile with the orcs who murdered them and the blood elves who stole their last hope of escape and kidnapped their friend and ally to drain him like vampires feeding on a corpse, than they have their own people who committed no crime save enduring a horrific ailment, a demonic affliction forced upon them.
With the example of Nobundo and the signs of regret over their initial actions (the draenei presence in the Swamp of Sorrows shows that they're trying to reach out to their fellows who suffer as broken or lost ones) it's an interesting side of the draenei character, this unwillingness or inability to be as forgiving of their own problems. And it is one that should contrast against the society of Warlords, which will have (presumably) no large amounts of broken or lost ones to deal with.
There's a lot more to muse about, but for now it's enough to consider. We still have many, many stories of the draenei that are completely unknown to us, tales of their wandering through the dimensions, seeking a home somewhere in the infinite blackness. Perhaps Azeroth is that home, or perhaps it still waits for them. At least in Warlords we'll see them as they were before Kil'jaeden's vengeance took such a terrible toll on them. But there will be so much left unanswered.
While you don't need to have played the previous Warcraft games to enjoy World of Warcraft, a little history goes a long way toward making the game a lot more fun. Dig into even more of the lore and history behind the World of Warcraft in WoW Insider's Guide to Warcraft Lore.