I'm going to be honest: I could never get into Warcraft roleplaying. RP can be hard enough with the different approaches people have (accents, interpretation of lore, Pollyannas), but in-game mechanics can often make things incredibly difficult. For example, in past games, I knew people who refused to RP in any channel other than /say. Why? Because they felt that only psychic characters would be able to communicate across mountains without cell phones or other modern-day conveniences. It's a bit picky, but I get it.
What about other things, though? Our players constantly come back from the dead without an explanation. From Asheron's Call to Rift, other games have made the death situation take a front and center position in lore. AC characters are magically bonded to lifestones for a seedy purpose unknown to them for several years; Rift players have spirits anchored to the world via technology or divine intervention; and WoW players ... have more resilient ghosts than most NPCs? Or at least, most of the time, since Cairne was ganked a lot prior to Cataclysm and always came back until someone gave Garrosh a poisoned blade.
How do you deal with game mechanics when RPing? Are levels "birthdays"? Is earning an achievement an epiphany? Maybe cross-faction dungeons with instant transportation are similar to finding Dr. Who's telephone booth?