There is and never will be anything that quite compares with partnership experience.
A discussion hand presented itself the other day, on a telephone call with a favorite partner of mine, Ken Eichenbaum.
The problem was this. Your partner opens 1S, opponents passing throughout. You respond 3D, which conventionally shows an invitational hand with hearts (looks like a high-end weak two to an ugly one-level opening you should be ashamed of, perhaps). We do this to gain a smidge of extra preemption in the 1S-P-3H auction, with one-under being the high "Bergen" option.
Anyway, that specific call could be 3H -- the point is the same. Opener next bids 4C. What's that?
As if in sync, we both kind of just knew the take on the auction that we would each have, if playing together. 4C is either a slam try agreeing hearts or a spade-club two-suiter with values. That part seems obvious -- it has to be one of these. But, it could be either. Responder, uncertain which, would clearly opt for a 4D call to unwind this, Opener bidding 4H when he has the power heart raise but 4S when he has the black suits. Because Opener knows what Responder would do out of the context of discussion, and because he KNOWS what THIS PARTNER would do, he can "safely" bid an undiscussed 4C in either situation, knowing that this will be unwound properly.
Partnerships benefit from a lot of discussion. "Weird hand came up with Johnny last night. Here's the hand. Blah-blah blah to you." "Um, I suppose 4D works." This type of discussion, and the actual experience at the table, gives the partnership a comfort level that expands the realm of "undiscussed sequence" into "undiscussed but with principles and theory known." Practical works a lot. But, sometimes practical just won't do. Sometimes, discussion just wasn't likely (who discusses this sequence?!?!?). In those situations, the only thing you have is logic to resolve situations where only one meaning is possible, despite discussion, or understanding of style, when two options are plausible, often coupled with unwind opportunities.
There of course is always a risk of a misread or a panic. But, sometimes that possible risk is lower than the known risk of NOT trying out the ambiguous, undiscussed action.
Of course, CRITICAL to this sort of partnership is one key requirement. You can be aggressive or passive. You can be naturalist, scientist, or a madman. But, be internally consistent and predictable to partner.
That's not to say that variation is not a good thing -- situations call for different action and some level of randomizing. But, "consistently randomize" in the right situations so that partner will know that this is a situation where randomizing is possible, or even likely, if that makes sense.