Yes, it was our intention all along. That's one of the main reasons why the first chapter is the longest in terms of missions... it's the most linear one, there are no previous choices that require extra voiceovers, extra fiction, or extra missions. In this chapter there are just mission variants (fail M2, go to M3B instead of M3A, etc.) but not actual branching in the mission tree (since M3A and M3B have the same overall objectives, we consider them to be one mission even if they're actually two).
Chapter 2 is still like that in terms of missions (just variants, not branching), since the story always starts at the same point (the end of the false peace)... but in terms of dialogue and fiction it already has two very different paths depending on wheter you've covered for Sparrow or not.
Then from Chapter 3 onwards, each chapter is really two Chapters in one, since each has a losing path and a winning path which start at different points depending on your performance in the previous chapter. The missions in each path are totally different from the missions in the other path, and there are now mission variants within each path. So when we say Chapter 3 has 4 missions, we really mean it has 7-8 missions, and at least half of them with A/B variants.
(It's just that in any given play-through of the game, Chapter 3 can't last over 4 missions.)