With the Reward deck coming in Expansion 1 (Cosmic Incursion), let's hope that the Hazards materialize in the next expansion.
20 more aliens sounds likely. There will no doubt still be a lot of previously published aliens to choose from (Eon and Mayfair), and certainly no shortage of new alien possibilities.
7th color? The Destiny deck does have several colors not in the game, though they are probably a little too close to the purple color. I'm thinking Brown, Gray, or even Black as a possible new color. Maybe some marble-multicolored ships?