I assume you're working on a MMO game, I'd say make the game accessible, but hard to master.
As suggested previously, I think a high risk/high gain pvp system can be pretty good, that way you can keep hardcore MMOers (just made that up) interested, but don't forget to make the rest of the game enjoyable for the casual players.
Adding hard areas/quests/dungeons with great rewards when beating a boss/completion is a good idea, people will level up to clear those areas and get the precious loot and then search for more.
Auto attack works, but can get boring at times. If you can make a good "skill" based manual fight control, it'd be great, many new MMOs are trying that and it sure is fun, the only "downside" is there's not really a big open world, just cities to trade, get training, join parties, etc., and stages for the quests/missions/pvp.
If you don't want to read everything: make the game easy to aproach, but rewarding for the most skillful players.
ps: glhf, on the Starcraft reference, from what I understood, you basically want the game to play itself? I mean, if you don't have to control your units anymore, then you're not really playing. If you mean only the SCV's and production of units, it'd make the game so much easier