This thread is very interesting....
Clearly there is a wish for more automation from some people. I think BPP is a wonderful example of what automation can be. I makes assumptions which may not always be optimal, but allows to get a decent result without much tinkering. You want better ? You can tweak. You want even better, don't use BPP, and use the "bricks" that make BPP.
I bet you, that BPP is one of the most used routines in PI. I think that fact tells a lot about how people want to use PI.
Right now, to me, PI has a lot of those "bricks", but few "meta-routines" like BPP, which make processing much faster, with "pretty good" results (without tweaking). Is it a black box ? If you want, you can know what goes inside. So no, it's not a black box in my opinion. It is a meta-routine. Nothing opaque in there. IF there was no documentation and the routines could not be read to know how they work, then it would be a black box.
Since some of the routines take quite a while to run, it could be nice to have the system automatically generate several "variants". Yes, it would take even longer, but you could go for a coffee, come back, and have (for example) 5 different images calculated, with 5 levels of noise reduction, and choose the one you like best.
But an even better solution would be a "meta-routine": first evaluate the noise level (there are routines for this in PI), evaluate (for example) the noisiest wavelet layers, do some other analysis, and then apply the noise reduction that has found to be "best" for this noise level. Yes, this takes time to test and calibrate, but once it is done, it could be quite efficient. Of course, some people like more noise reduction, some people less - but at least it would be a starting point. The routines are there, but effort should be made to automate - using the existing tools.
It is also clear now that the PI team has no interest in automation, and that this burden will fall on the users. I feel this is disappointing.