Definitely a move that is to earn mixed views from its fans, Blizzard has decided the next Starcraft installment will have to be released as three separate games to give enough material for each race and for a greater story arc. More on this here.
I say as long as the following things are incorporated somehow into this trilogy, then its a good move:
1) All three races SHOULD BE PLAYABLE for multiplayer games for each segment of the trilogy. So whether I get the first, second or last pack, I can play Terran, Zerg or Protos for multiplayer games.
2) Each pack should still add something unique for the customer. So even if I only get the first pack, I have an incentive (other than additional single player story to go through) to buy the others. Typically this means more units. Take for instance the Dawn of War series. Each pack added a new "race" to play" as well as additional units to use. What they did wrong was, the pack you installed limited what you can use for multiplayer. And that majorly sucked.
3) Each pack COMBINATION should add even something more unique. Maybe installing packs 1 and 2 give an additional race as well, which is different from the additional race you get when you install packs 2 and 3 instead. And of course, if you install all 3 packs, you get both new races as part of your game, as well as a third new one for having a complete set. Or maybe this can be more freebies. Behind the scenes videos. Sketchbook designs. Maybe even comic graphics showing the story of certain favorite characters.
4) Each pack should also have new inventive maps for solo or multiplayer other than the typical game. Think of a DOTA type of game using Starcraft. Or maybe a few Tower Defense Maps. Or maybe even a RPG style map.
5) If Blizzard is really smart, they should also consider making MULTI RACE options in the game. Something like HYBRID RACES you can access depending on the games you install. Maybe if pack 1 is Terran focused, and pack 2 is zerg focused (as far as the story is concerned), maybe installing packs 1 and 2 allows you to access Half-human Half-Zerg units. This is in line with idea #3, but deserves to be mentioned since it uses existing units with certain modifications and changes. Or maybe even an alliance system where you can have a Protos Human game (controlling BOTH bases alone) against someone else in multiplayer with their own combination choices.
6) I would love to see a third game mode, where you choose a hero who can be "leveled up" like in Warcraft III. Though the mass combat RTS of Starcraft is what I miss, I would love to see them adapt the WC3 gameplay into the game somehow as an option.
Of course. These are all wishful thinking.
If only Blizzard hired me, eh?