Re: How effective do you feel weapons should be
Of course if one looks at RL technology, offense is pretty much always going to be stronger than defense. We're close to the capability of pinpoint-vaporizing almost any known material. That's why armor of all types (for vehicles, personnel, buildings, etc.) is and will probably always be a secondary defense. At present force field-like technology is entirely in the realm of rubber science; and there's no reason to think that if we do develop FF tech, it will behave any differently than armor in that respect.
At the same time, when we speculate about advanced space travel, we almost have to assume some pretty serious defensive capabilities. The energies one has to handle at near-c and/or in extreme stellar conditions are way beyond anything we're even close to. In which case, maybe it's not so outrageous to think that a warship could repel a ground-zero nuclear blast.
Just thinking out loud.