In Starcraft II the map is pre-loaded and the character sprites are not nearly as large as in XIV. O_o I don't magically see sprites rendered as they enter my sight range in SC2 and that's because it's a much lesser load. Likewise the textures for the maps are not that large either.
In XIV the map must be drawn and rendered every time you move the camera, every time you physically move and everytime something else must draw an emote/move. Every time a PC or NPC appears in your range it must be loaded, drawn and stored. So, no, this game isn't really putting an unrealistic load on your GPU compared to other games.