My reasoning for reading Rise of the Horde over again, was that I wanted to get a better grasp on the hard facts. When did this and that happen, how many were they, and so on.
- Less than 1 000 draenei escaped from Argus.
- About 25 000 years later they crash on Draenor, and they were then about an even number with the orcs, or slightly less. Without it really stating how many orcs there were on Draenor either. Velen states in Rise of the Horde that since the draenei are very long-lived, they don't have children very often. So I really don't know how much they've increased their numbers in those 25 000 years. Neither do I know how limiting Genedar/Oshu'gun was on space. 1000+X=Y draenei.
- The orcs killed more than 80 % of them. 20 % of Y=Z.
- About 70 years after the orc-attacks started, the draenei crash on Azeroth, with unknown losses.
- With WoD's time-/planet-/reality-jump, we're back only 35 years in time, and by that time in our history the draenei had already suffered major losses. However, alternate timeline Draenor seems to be holding up much better. So the combined number of draenei between the two realities seems to be approximately Y+Z.
- However, if we leave beautiful Draenor, and close the portal behind us, we're again down to Z.
I've seen people argue for this being the case; we go there, we save the day, we go home again, we close the door. Well, I hope this isn't how it will turn out. My characters have undoubtedly had a hard time going back, but after spending a year or two on a Draenor that is whole again, see their culture, temples and cities "restored", meeting people they have lost in our timeline, and perhaps even getting new friends... I can't really tell them that this is something they will have to leave behind.
Here's the timeline I made, with a lot of help from Wowpedia.