I'm for flat-faced joints that put wood to wood. The idea of putting steel or ivory between the union of wood shaft and butt is absurd to me. I want resonance transmitted to my stroking hand. Putting ivory and particularly steel between wood ensures that the resonance and the audible report it makes will be compromised.
Balance point, shaft taper, butt diameter and weight are simple issues any capable cuemaker can adjust to the needs of the user.
As for construction, I favor joints that put a large pin into wood. Radial, 3/8-10 and 3/8-11 in either steel, brass, titanium or g10 all work fine. The pin material choice is more about fine tuning balance point and weight than what it does to the hit. With that said, I have hit a couple of cues lately that used a g10 pin. Both hit nicely. So I'm not sure if it was a function of the pin or simply that they were well designed and made cues and the pin was coincidental.
I'm becoming increasingly convinced the best hitting cues use an A-bolt to join the handle to the forearm. This, opposed to a full core. My theory is full coring produces a very solid but dull hit, with little feel. I've been talking to a pro player friend and with his cuemaker about this. The cuemaker had gone to full core butts, but agreed to make a couple of test cues without any coring and employing an A-bolt so that we might compare the two designs. When those cues are ready, I'll give you all some feedback on the result. For what it's worth, I very much favor the hit of Southwest cues, and the player I mentioned also favors the stiff, resonant hit of a SW (he wants mine!). So that is the type hit we're looking for.