Lack of an actual fail de-games a game too much for me.
I don't mind a range where complicated success is allowed, but there are times where I want a real failure to be an option, and that's most of the time.
I think you bring up a good question that is hinted at in the whole mixed success and fail and both etc etc =
What actually is "Fail" ??
To me... Fail means "...it didn't go as I wanted it to."
and Fumble/Botch means "....I screwed it all up and made matters worse"
However, both of those could still possibly include "I did the action I was trying to do, but...." (then append one of the results above)
So Failure is always an option... it just never "Fail = nothing happens"
...
What is a situation in which "Fail = nothing happens" , is
more fun and engaging than "succeeded with complications?"
......
Note that "fail with opportunity" is really the
exact same thing as "success with complications", just phrased different....
"You failed to complete the task as you intended, but
you still acted and did things and
stuff still happened. It just failed to resolve as you hoped. Which could be: it worked with less effect, it costed much more, it allowed the badguy to also get a task completed, the thing didn't work but its also not busted so you can try again, you didn't see anything but nobody saw you either, etc etc... "
....
The idea behind
success with complications being better than 5+tiers of success/fail and better than pass/fail = is that it is the way to acknowledge that the character in fact did act, they did something, and that failure is never just 'nothing occurred at all from your action.'
It also asks everyone to consider 'failure' is more than 'you don't it at all' = far more often 'failure' is based entirely on very different possibilities - none of which are 'nothing happens'.
A typical example of this is "Roll to climb the wall", you fail the roll, you don't climb the wall. = what a boring result
Some games go so far as to
punish for a failed roll, "roll to climb the wall. you failed, you fall and take damage". = ok fine, but what a tedious and one-dimensional result. Every time, always 'take harm' result, bleh....
But that is far from the only result 'fail' could mean.
If we go with PBTA's dynamic of success with complications we get a better paradigm for keeping the game going and engaging players for fun. "Roll to climb the wall, you failed(Success with Complications), you made it half way up and you panic and freeze, you cant will your arms to go up or down." or "you failed(SwC), you made it up over the wall, but there were spikes at the top, and you cut yourself, take harm but you are up there", or "You failed(SwC), you can't seem to find footholds to climb this wall, but you are able to take a long time to make ropes, sticks, and other things to shimmy up the wall, you are up there but it took so long the ceremony is already started!" etc etc
Every single Success With Complications is the kind of fun and drama people love, and it keeps the game moving on, and it lets the result "let things happen"... we did stuff, so stuff should be done...