Yeah, the early game is still filled with scripted missions. Further frontloading it with the loooong SPARK and Alien Hunters stuff would kill momentum.
The DLC missions are kind of a bugbear I have with XCOM 1 and Enemy Within. They suffer this flaw being a string of long, very gimmicky missions that are basically a death trap if you don't understand how they work. So I'm glad Firaxis are learning from those (IMO) mistakes.
Playing it safe and having a few 'Excellent' missions ending like this:
(The only reason this isn't a full wipe is because the RNG gods were with me. One person was unconscious; one was near-death for most of it; and an Alien Ruler showed up at one point which slowed me down to the very end of the timer. If I didn't have a grenadier capable of blowing up a wall... oh man.)
Victory is suffering.
On this note, having a mission or two in a row end like this is, while lacking an infirmy... problematic. There's such a web of interdependancies between soldiers now, so much more to consider during loadout, that sending suboptimal squads is a long-term mistake. Building those bonds makes every difference.