I think, at the end of the day, that it's all about knowing our materials.
Mistakenly, early in my photographer days, I was very keen on trying to improve by switching films, developers, and so on, but in the long run, it's technique that matters. It only took me five years to realize this.
Today I have established what materials I like to use, and it's mostly stay with one film/developer, and one paper/developer. I don't think I'm even close to reach their full potential, and wonder if I ever will. But I think to try to fully explore our materials is the type of progress we should explore, because that approach makes us think about the pictures rather than thinking about the materials, and a print can be absolutely glorious in print quality, but without a good picture underneath, it's still not interesting. The whole process easily becomes too much about the wrong stuff.
To find that balance between technique and subject matter is what I find to be the most challenging aspect of photography. I hope to continue learning about the materials I use, about lighting, about color (even in black and white), about framing, and about printing technique. I feel like a perpetual student. Someone else always knows something I don't. That's why the advice of someone like Bob Carnie is of invaluable help to me. The advice he gives me will be time proven in practical use.
So, to summarize, I think that all magic bullets are technique related, and none of them related to particular materials. This is my approach, and I admire others that can make beautiful or important prints using other approaches. There are many ways to get to the end result, for sure, so in my mind it becomes impossible to answer whether one developer is better than another. Just pick one and run with it and make the most of it. It isn't until you fully understand one developer that you can fully exploit and appreciate the qualities of another developer anyway, so either way you win by learning one developer first.