This says a lot about my brain (great at music and sequential tasks, terrible at juggling multiple simultaneous tasks), but it also says something interesting about the nature of these two games.
When I make a mistake in Rock Band, the game makes sure I know about it that very instant: A piece of the UI shatters like broken glass, the audio for the note doesn't play properly, my performance meter goes down, and my note streak is broken. On top of that, notes show up hundreds of times per minute, patterns of notes show up many times per song, and each song is short enough that it can be replayed many times in an hour.
Because of this, Rock Band is one of the easiest games to learn. I don't necessarily mean that it's an easy game to be good at, but it is an easy game to get better at. If even the worst beginner sits down and plays the same song a few times in a row, their performance will immediately start improving.
Conversely, losing a game of Starcraft can take hours, and I can never really pinpoint where I went wrong. Something very early in the game, such as making the wrong number of harvesting units, or failing to expand at the right time, or deciding to progress down the wrong tech tree, can have adverse effects much later. This problem is also exacerbated by the fact that Starcraft, like most strategy games, is a slippery slope game.
Timely information feeds learningGames like Starcraft and Chess, which can have long periods of time between between decisions and the consequences of those decisions, are very difficult for players to learn. This shouldn't be too surprising – any book on pet training, child rearing, or romantic relationships will tell us that a delayed reward or punishment for an action is confusing.
Your dog can't tell that the treat you just gave him is for the trick he performed 20 minutes ago, and your significant other will only be frustrated when you snap at them today because of something annoying they did last week. Gamers are the same way – the more immediate the feedback to their actions, the more quickly good and bad behaviors can become reinforced.
Strategy games obviously delay their consequences on purpose, and I'm not saying Starcraft should be redesigned to be more like Rock Band. However, I do think Blizzard could add in some sort of special learning mode that would notify the player in real time of mistakes that would not normally be apparent until much later.
If beginners could see status messages like “your economy is falling behind, try producing more gatherers” or “your factory has been sitting idle for x seconds” or “your opponent is producing tier 2 units already, time to upgrade,” it wouldn't help people become experts at the psychological aspects of the game, but it could help terrible players like me start to learn from their mistakes more effectively.
Feedback loops in game developmentJust as players learn much faster by seeing the immediate results of their decisions, so to do game developers. If we don't see results for too long after making decisions, it's easy to forget what the other options were, which of our arguments and thought processes were flawed, or even who was responsible for a particular decision.
Worst of all, if a game takes too long to make, employee turnover becomes a problem. Bad people get fired, and good people leave for greener pastures. If the people who witness the results aren't the same people who made the decisions, only the most disciplined designers will manage to glean any useful lessons.
Show me a game designer who has only released code to players twice in ten years, and I'll show you a mediocre designer who is learning much more slowly than they could be [unless they were constantly playtesting that whole time]. Most of the best designers I know have shipped many games in a short period of time, started out on live games where changes are released almost immediately, or worked at studios that are constantly letting people playtest their work before the game ships.
Like all designers, these people started out with a lot of wrong thinking about how to make games, but they very quickly had their bad ideas shattered and their good ideas reinforced. Just like Starcraft, success in game design is a slippery slope. The first year of your career as a game designer sets the trajectory for everything you will ever do, and if a player never even plays one of your designs until your 3rd year in the industry, you've already fallen behind.
For those of you looking to start careers in the game industry, try cutting your teeth on a live team or expansion pack team. Experienced designers usually choose to move off of these teams for the exciting new project, and as a result they are more open to newbies. Likewise, starting out by working on games with very short production cycles is another good option.
The average game project is getting very small these days, so it's a perfect time to start out as a new designer on an iphone game, flash game, facebook game, or live MMO. Shipping a lot of games now will give you the accelerated learning you need before tackling that masterpiece later.