There is an almost certainly apocryphal proverb that goes something like, “If you want to go quickly, go alone. If you want to go far, go together,” and I think of it often when trying to take on large/complex projects, because I see this thinking get a lot of teams in trouble.
One of the things we have to do when we, as designers, take on large projects is integrate complex sets of requirements; but that’s really hard to do with the “two-pizza teams” favored by adherents of this particular folk wisdom. Those teams are designed for speed, because (let’s face it) speed is almost always a requirement. That isn’t a bad thing. The longer a project goes on, the more likely it is to fail or get cancelled. Speed is a determining factor for most projects. The fault lies not in prioritizing speed, but perceiving it as a binary, and as a constant.
So, what do you do when you need to go quickly and go far?
I propose you oscillate between going together, and going it alone. Or, to keep things in the realm of apocryphal proverbs, you oscillate between Two-Pizza Teams and It Takes a Village. Recognize that there are times to go fast, skimming the surface and plowing through (or skipping off) surface-level disruptions; and times to slow down, sink in, and roll with the waves a bit. I know. My metaphors are all over the place.
This requires that you spend your time building a coalition of people who trust you and understand that there will be times that you will need their attention, and times when you don’t. There will be times when it seems like you’re ignoring them, and times where you will be joined at the hip. There will be times when you are asking them to weigh-in, and times when you are asking them to butt-out.
It takes an enormous amount of trust to get that last part to be okay; but that’s what it takes to do the big stuff quickly and well.
This, for what it’s worth, is why I end up being a proponent of facilitated collaboration methodologies like Design Thinking. At the points where you need to get input from that coalition, a well-designed workshop (or series) is a great way to get what you need from those people, while setting the ground-rules for asking them to get out of the boat so you can start going fast again.