Majoru Oakheart
Adventurer
There’s no game that takes twelve steps to resolve an attack. That’s as much an extremism as describing light games as just improv theatre. Sure, both ends at their absurd extremes cease to be useable roleplaying games. Pathfinder, the go-to example of a medium complex game, has two steps - roll to hit, roll for damage. For this conversation to even work, we have to use realistic examples of both.
I think if you factor in a lot of the optional steps then there are plenty. The problem is that complexity doesn't always translate to complication. It always has that potential, however.
For instance, my experience playing 3.5e was that the complexity(or the sheer number of options, if you'd prefer) always slowed down the game because it had the potential to exist at the table even when no one took those options.
You could reduce an attack roll in the game down to 1) Roll to hit and 2) Roll for damage. But within those steps there are many substeps. Those substeps all take time so they really need to be factored in. Even when the substeps don't apply during this particular attack, they still need to be checked to see if they resolve.
For instance:
Pre 1) Declare who you are attacking
Pre 1a) Can you see them?
Pre 1a1) If you can't see them, do you have a magical effect that allows you to see them?
Pre 1a2) If you have a magical effect that allows you to see them do they have a magical effect that counters that?
...
1) You attack them
1a) Do you have any bonuses or penalties on your attack roll from yourself?
1b) Do you have any bonuses or penalties from allies?
1c) Do you have any bonuses or penalties from enemies?
1d) Do you have any bonuses or penalties from the environment?
...
This goes on and on. If a particular substep happens rarely enough, you can mostly ignore it. But when it happens a reasonable number of times, you have to think about it each time.
Practically, this manifests itself as players constantly double checking rules because they can never be sure if the particular step was accidentally missed or it was missed on purpose. One of the most common ones used to be Attacks of Opportunity in 3.5e. Every time someone would do something that provoked one there was a constant barrage of players reminding the DM of all the things that could or might happen:
P1: "He left that square, doesn't he provoke?"
P2: "He might not provoke if he has X ability, that would let him move without provoking."
P1: "Unless I happen to have Y ability which would mean I still get an AOO"
P3: "Right, but then he could do Z to bypass that ability."
DM: "DO you have Y ability?"
P1: "No. But I might have and you never checked."
DM: "It didn't really matter, because as P3 said, he has Z ability which lets him bypass Y. That's why I didn't ask."
That situation could have been resolved very quickly: Monster just moves. However, in practice it took ages because of the number of options in the game.