The thing is if you get dealt new sparta as a start world and then you get dealt, I don't know, Old Earth, that doesn't really go with your strategy. But it's still Old Earth, and you can still discard it for other stuff, or you can still play it for its effect and switch strategies to something using Old Earth (Old Earth is probably a terrible example since it's probably not one of the most exciting reasons to switch over to a consumex2 strategy but bear with it). Or you could play Old Earth for just a minor involvement in the alternate strategy it offers.
With the goals if it flips "First to get one production world of every color", if you are dealt the wrong cards for that goal the goal just does nothing for you. You don't get any benefit for doing something other than the goal, like you do when you discard a card that doesn't fit your strategy. You quite possibly don't even get the option of switching over so you can achieve that goal, you can quite easily not draw the right cards for it at all.
So it just seems more luckish than the game is without them to me.