If it's only story, then a book or movie is more appropriate than a game. If the gameplay is repetitive, I might as well read a story synopisis online and be done with it.

Browder: We’re definitely looking at new units for each of the expansions for each of the races. When you get to the Zerg campaign you’ll get new Zerg units, new Terran units, new Protoss units. And we’ll look to see what we can do to improve Battle.net as we go, and we’ll look to see what we can improve in our replay system as we go, so it's whatever we can think of to do to make the product cool and valuable to our players.

You know, I just had a brilliant thought...

If you were to be rich enough and own all the three discs..
You can simply create the missions in UMS for those that are less fortunate =D..

The Cutscenes will probably be uploaded on Youtube anyways lol...

I'll buy the terran set and remake all the missions. Two other people do the Zerg and Protoss missions

What is the StarCraft II Trilogy?
The StarCraft II Trilogy consists of the base StarCraft II game and two subsequent expansion sets. StarCraft II is subtitled Wings of Liberty (working title) and will include a lengthy single-player campaign that focuses on the terrans and puts players in the role of Jim Raynor, one of the series’ main heroes. The first expansion set, Heart of the Swarm (working title), will follow later and include a single-player campaign focusing on the zerg and Kerrigan, Queen of Blades. The second expansion set, Legacy of the Void (working title), will continue the story experience with a single-player campaign centered on the protoss.

Will we still be able to play multiplayer matches of StarCraft II with all three races?
Yes! From the beginning, StarCraft II will be a fully featured multiplayer game, and all three races will be available for competitive play.

How will the expansion sets impact multiplayer gameplay?
The expansion sets will add new content to each race for use in multiplayer matches. This could include additions such as new units, abilities, and structures, along with new maps and Battle.net updates.

If I buy StarCraft II but don’t buy any of the expansion sets, will I still be able to play online?
Yes. This will work similarly to Warcraft III and the original StarCraft, which maintained separate online gaming lobbies and ladders for expansion set players and players with the base Warcraft III or StarCraft.

How long is each of the campaigns?
StarCraft II’s terran campaign will consist of approximately 26 to 30 missions, and each expansion set will include a similar number of missions. This means that the complete StarCraft II Trilogy will include as many as 90 single-player missions. This allows us to create a truly epic story experience with a great variety of unique missions and gameplay types.

Why did you decide to release each race’s campaign separately?
We’re aiming to push the boundaries of storytelling and character development in RTS games through the unique single-player campaign design of StarCraft II. Players will be able to choose their mission path and technology upgrades for their army as they advance through the campaign. In order to make these choices meaningful while creating an epic story and well-developed characters for each faction, we needed to focus on a single race for a large number of missions.
The Trilogy also allows us to create more in-game and prerendered cinematics to tell the story in between missions. There will be more interactive sets and elements for players to explore during each campaign, along with other interesting design elements to differentiate the single-player game from multiplayer matches. For example, the technology choices within the terran single-player campaign will include special upgrades and unit types that are unique to the single-player game. These could include the ability to purchase classic units such as the wraith or firebat to add to Jim Raynor’s army.

Are these three separate games? How much will all of these games cost?
The StarCraft II Trilogy will consist of the base StarCraft II game and two expansion sets. Pricing on these games hasn’t been determined at this early stage; however, we’ve always charged an appropriate price for the content the player receives, and we will continue to release high-quality games that offer great value.

How long will it take to ship each expansion set in the Trilogy?
We’re still focused on developing the base StarCraft II game, and all the content associated with the terran campaign, including the missions, cinematic cutscenes, and interactive sets. It’s too early to provide an estimate on how long it will take to develop each of the expansion sets in the trilogy, but as always, we will take as much time as is needed to create the best possible gaming experience with each expansion set.

I'll buy the terran set and remake all the missions. Two other people do the Zerg and Protoss missions

Cutscene cinematics with the MPQ extension are included with Warcraft III and, despite the file extension, are not actual MPQ files. Rather they are AVI files compressed with Blizzard's renamed MPEG-4 codec, BLZ0 (which actually is DivX). These files are playable in ordinary media players, provided the proper codecs are installed. It is not known why Blizzard used the MPQ extension on those files. In addition, World of Warcraft cinematics use the AVI extension.

DBC (WDBC) files are collections of data records used in World of Warcraft's client-side database. They are found within the MPQ files in the game. .DBC files organize the client-side information necessary to run the game correctly.

Not really. Like Rantent said, this is a big deterrent to mapping. Not all of the units will be available in the terran set, just like not all of the units were available in vanilla SC. Getting TWO expansions that cost just as much as the original is more than a bit stupid, and restrictive. They could easily just put all three together in one box as one game with three discs.

Why would you want them to? It wouldn't make a tiny bit of difference how they release their stories. 3 in one with 2 more expansions or a trilogy. And you are forgetting that SC2 will be able to make your own units through the editor. There is no such thing as 'limiting units'.