Formations can be translated to team builds in GW2. There are quite a few more "formations" in GW2 than soccer (which makes it more complex and that works the other way around, makes soccer simpler).
Most options in soccer(any real sport actually) are binary "playing in the foot vs in the field", "go through the sides or through mid",... Which are very easy to understand and respond to. Compare that to chess where you have infinite amounts of possibilities.
Now let's (for giggles) that chess is the most complex "sport" out there and let's compare soccer, GW2 and SC2 to how similar they are to chess (and thus how complex they are). It's probably quite obvious that SC2 is most like chess, then GW2 and lastly soccer. Meaning that in comparision to sports soccer (and as said earlier most real sports) are rather simple.
The number of starting positions in soccer are finite, in chess they're infinite...