Yes, we must never lose sight of the balance between casters and martials overall. On the other hand, if Fighter viability hinges on choosing GWM or SS/CEx, then that is exactly the sort of narrowing of strategies that we don't want to see. I believe the next step in this process, is to make a similar assessment of casters. My sense is that D&D's balance rests (or should rest) on the following pillars
the primary pillars are
presumably not always in that order
secondary pillars include
- melee weapons are best in melee
- sneak attacks and two-handed melee weapons do the most single-target damage
- single-attack classes scale as strongly as multi-attack classes
- range has a value and comes at a price: about a third less damage
- casters do the most AoE damage
- skill classes - Rogue and Bard (and maybe Ranger) - are best at skills and tools
- caster utility is powerful, but strictly finite
- the highest AC defense is the heavily armoured, defensive martial with shield
- one handed melee weapons are best for defense, good for crowd control, and sustain mixed fighting styles (e.g. sword and hand crossbow)
- caster crowd control is powerful, but strictly finite
As fighters have come to rely more and more on finite resources (action surge, superiority dice) they've come closer to parity with spells. Formerly, I think the assumption that the fighter could fight all day, and would balance out more powerful spells, turned out to be a false hope. Hence I think we can now look at spells over 30 rounds and come to some better conclusions.