It was similar to what you are talking about. There was an RTS aspect with a tactical view where you ordered groups of units around, and an FPS aspect where you fought as an individual.
The gameplay was based around your tactical units being under balanced against the enemy, so you would have to choose where and how to use yourself as the superweapon to achieve the level objectives.
I was a developer on the game team which had representatives from the RTS and FPS teams (CnC and Medal of Honor). The first day you were on the team you had to play the lo-fi prototype which had the basic mechanics in place. It was frantic, exhausting, frustrating, and incredibly fun.
Obviously I can't talk about why it was cancelled, but if you look at the business environment and economy in the first couple of years after the xbox360 and ps3 were released, you can get a good idea.
I really wish that game had been finished and released as it was originally conceived.