Both factions have groups who do that, Chris. Just a matter of finding them if that's what you're looking for.
You're dead right. Thing is, for World of Warcraft, since Vanilla, the Horde with it's 'ugly races' has been home to (not all) people who look down on those who choose their class based on looks, which are mostly (not all, but typically more than half) casual players, who want something cool or pretty to look at. And because the Horde side races tended to be uglier, they tend (again, generalization and not all do it) to focus more on stats, and builds and getting the most out of what they play, which they find fun. Also, the Horde tends to draw those types of people, because the original player drag friends in, who are typically like minded.
Does that mean they don't RP, or have no casuals? No. Hell no. What it means is that there's less of them, usually. And one of the reasons that Blizzard (and I wish I could find the article) made the Blood Elves go to the Horde side was because of a large population imbalance. More people played Alliance. I believe PvP was cited as a reason for trying to get more Horde players, but it never needed it because despite the smaller Horde base population, more of them actually PvP'ed regularly, then the Alliance side.
(Example (and these are BS numbers I just made up, but the concept remains the same) Although Horde may have had 70% of the Alliance side, they still had a 90% PvP rate, as opposed to the typically 30% of the Alliance side of dedicated PvP players. Again, made up numbers, but that was the issue that Blizzard tried to use the Elves to get people to play Hordeside. Which caused a huge uproar on the Forums at the time of Burning Crusade, and people STILL look down to this day.)
Again, not all servers are the same, and everyone can RP. But because Alliance tends to be more casual, there's a better chance of finding RP.
Will it be any good? I have no idea. Because to me, if it's got a plot, and a story line, I don't care if it's got cybersex or thinly disguised mary sues or cheap comic plot. As long as it's fun, I'll do it, if people will have me.
[Tongue in Cheek]
Besides, if you want to play the true villains of WoW, you want to play Alliance. The Humans are racist jerks (Hey, let's kick out our Allies the High Elves, you know the ones who've been with us for nearly a millennium and taught us Magic to fight their enemies the Trolls, because... I have no idea, actually), the Night Elves bemoaning their lack of Immortality to the point of siding with Demons (TWICE), the Dwarves are brilliant, short sighted scientists (Their focus on the Pantheon and willingness to disregard the warnings) and idiots (What kind of moron let's the treacherous queen of the enemy kingdom sit on the ruling council?) and Gnomes? Well, they're just incompetent. Not only do they literally nuke their own home, they irradiate/drive mad all the survivors, and still don't get rid of the original issue, the Troggs. The Draenei's biggest problem I suppose is their singular lack of direction and piloting skills (they crashed their Dimensional Space Boat on an island and completely totaled it and the island), although the fact that a good chunk of them got corrupted and have been most of the 'demons' of the Legion for almost time immemorial, and the other chunk are devolved morons...
[Remove Tongue in Cheek]
And most of the Horde's problems were caused by Humans in some way.