The ONLY reason I would ever pick a Blood Elf is for a Paladin, because there is no other choice for Horde.
When you compare the racials(the only thing that set races apart in terms of performance) The Undead racials are great for PvP, and the Trolls racials are easily the best for a rogue for PvE. You can choose Orc as well, they are good in PvE, but not as good as a Troll, but better than Undead. They are good in PvP, better than a Troll, but lacking when compared to Undead.
If you need to know why, just look at the racials, they speak for themselves in my opinion. --- Rule 1. I am always right. Rule 2. If in any case I am wrong, refer to rule 1.
Undead and Orc Rogues are the best. Orcs are good for the extra 15% stun resist and bloodfury, and Undead are good for WotF and Canabilize. Personally I like undead much more since they fit the class better :D --- [ d r i f t ]
As for BE not having good racials, I'll laugh at that.
You wouldn't be the first, but it really doesn't matter if you laugh at it or not, truth is, there are better racials. --- Rule 1. I am always right. Rule 2. If in any case I am wrong, refer to rule 1.