Certainly game doesnt have to have realistic graphics or style, look at Minecraft for example. Even World of Warcraft had a cartoony look but the whole game was based of Warcraft 3, so it was to be expected. Incase of SWTOR they could have gone a bit more like their cinematics or Star Wars The Force Unleashed style.
Well it's only my personal opinion and it does not change the fact that overall the game will probably be pretty successful. Now it only has to overcome small obstacles, stability issues and providing content for the players.