Well, straight push rod angles, 55mm cams, vacuum pumps, dry sump systems, rocker arm geometry, heavy vs lightweight crankshafts, steel vs aluminum rods, ring packs, ect. all effect longevity IMO. If you want to make more power, add CI, heads, camshaft, compression, and fuel system that works with the CI you choose. Then match the converter to that combo.
Weight of the car is always a factor as the old saying goes, "less is more". That said, lightweight crankshafts only RPM faster. They don't really make more power unless you're a comp eliminator guy and use 7" converters and even then the improvement is minimal. A center counter weighted crankshaft weight a lot more than a non center counter weight weighted crankshaft, but it is much less prone to cause main cap chatter.
Look at the stock/super stock/comp eliminator guys. They get the most out of their parts, and they are pros at picking the right converter for their combo. That is the key as mentioned early in this thread. JMO
By the way OP, this is the best post I've seen hear in a long time!