Nah, they should act like that most of the time.
Randomly gathered some ideas about the original possible story about night elves and blood elves among other stuff, and why it changes the trajectory so much. Maybe you saw those sources already, then feel free to skip the thing.
How dare you!
Honestly if you listen about the original comment from Metzen about night elves and blood elves, their presence does make a lot of sense. But… (a little more in the mentioned post).
Could blood elves deliver M’uru faster than draenei go to here? Idk, maybe.
[M’uru was captured before draenei got to Exodar, that’s I’m aware of]
There isn’t much room for “much”, since vanilla was “done” it 1 year (year 25), and TBC too (year 26). So, whatever is the difference in time, I am not sure it would be more than a month difference. Events are extremely packed in the WoW story.
gl hf