My first suggestion is directed towards Blizzard. It would be beneficial to Starcraft II if they introduced a micro-transaction system. There should be skins, decals, and portraits in which can be purchased through both micro-transaction (1-2 dollars per skin, or portrait etc,) and through an in-game currency. (5500 minerals). You would be awarded 150 minerals per win that you get one the ladder (ranked and unranked, or in the in game tournaments (mentioned later). If they added 4-5 skins per unit, around 50 decals, and 100 portraits the game will have more funding to accomplish it's goals. I also believe that a recruit a friend bonus, that awards minerals, or micro-exchange currency would be beneficial to Starcraft as a whole.
Several Blizzard employees have said that they will not be adding in large amounts of skins due to it using additional memory, my suggestion is to do the following. Have a new tab in the settings called skins, where you can enable/disable specific skins, or all skins client side. This will help users with lower end computers.
I believe the first suggestion on it's own would encourage smurfing, and so I have come up with an idea to help prevent smurfing, in which instead of being awarded just 150 minerals per win, you are awarded 150 minerals multiplied by your fortune. Your fortune would start and cap at 100%, however every loss that you have reduces it by 5%, and every win increases it by 5%. This will help to discourage smurfing by implementing a minor incentive to avoid loss.
Moving on to my second suggestion. My second suggestion is to introduce an in-game tournament system, both ranked and unranked. The unranked one would be free to enter, have no prize money, and would just introduce players to the tournament format. Whereas the ranked version would cost 1-5 dollars to enter, and the prize money is equal to half of the total entry fee (the combined expense of all the people who entered) For example if one hundred people enter, at one dollar a person the prize pool would be $50.00, and Blizzard would keep the other 50 dollars to help them fund for additional projects.
My third suggestion is one that is very opinionated, and may be disagreed on. I believe that the damage of all units should be toned down, to make the game more friendly towards newer players. Instead of buffing the damage that units have, I believe that they should ether nerf the damage that other units are causing, or buff the health of that unit. I also believe that balance wise it makes a lot of sense to introduce few additional properties (such as massive, armored, or biological.) These properties would be Zerg, Protoss, and Terran. This will make it easier to directly target a match-ups balance problems without harming other match-ups. For example if high templar were over-performing vs zerg they could change it to read: Deals 80 damage over three seconds, or 60 damage over three seconds to zerg units. (Not saying that high templar are over preforming it was just an example.)
My forth suggestion is another that many may disagree with. I believe that a new unit should be added every 3 months or so for every race, (in between they would be balance tested) this would open up a near-endless growing set of builds for every race. The risk for this is effecting balance too much, and so the units would have to be testing carefully between, the other risk is that their will be too many units one day causing players to feel overwhelmed. So I believe they also should occasionally remove units (most likely one's that were added).
My fifth suggestion is to get the community more involved, allow us to volunteer to help with projects. I may not be a coding wiz, but I would be willing to help in anyway I can for free. I am certain that there are others out their just like me.
Finally my sixth and final suggestion for Blizzard (I also have some suggestions for the community) is to have a twitch screen, where people can view twitch channels and set up a twitch channel to be shown their. As well as offering some in-game rewards such as special skins for reaching x amount of viewer-hours on twitch. For example a special marine skin for reaching 100,000 hours of viewer hours. (Number of hours streamed multiplied by number of viewers). I believe that if blizzard were to introduce all of these suggestions Starcraft will grow drastically, and hopefully become one of the most viewed games on Twitch.