The single largest problem with elemental damage is that it doesn't scale with your weapon. That is the biggest benefit physical classes have, not any school division. Resists are stupid and a secondary problem, but not the biggest. Usually.
All physical classes want to invest 10 into Warfare.
An elemental caster can do similar by dumping 10 into their school of choice. I'm not clear on whether or not elemental schools are additive or multiplicative though (not like it really matters in the end). Problem is when you come up against those 50% - 100% resistances that you know full well about. Physical has nothing comparable to deal with.
The scaling point is an important one. I do not think it is an issue right now because the lack of damage situation can simply be remedied by cutting enemy resistances (going back to your chart now). The lack of scaling will be a major issue going forward if there is an expansion/DLC raising the level cap because casters plateau when the key skills are maxed out. This means that the only way you can improve your Fireball damage after maxing out Pyro is investing into ancillary skills like Two Handed and Huntsman, whereas physical classes get the benefit of the ancillary skills AND weapon scaling.
Physical classes DO need to invest in other schools too for better mobility options, especially Warriors. Scoundrel builds do by default simply because they are going to need at least two into Scoundrel for a while for skills anyway, but their primary way to raise damage is through Warfare (plus they have the advantage with not only Backlash, but their AP to damage conversion in general seems way more efficient throughout most of the game). Same thing with Rangers and Huntsman.
So my latest playthrough was a Lone Wolf duo of a Ranger and a Warrior with 2H. I went the crit route so I did have points in Scoundrel for C&D but this was just a cherry on top of the cake (mostly used outside of combat) because Warfare already catered for all of my mobility needs. Phoenix Strike for instant reposition, Blitz Attack is essentially a ranged attack with repositioning, Battering Ram for reposition with CC as an added bonus, Battle Stomp is essentially a ranged AOE attack with CC to boot, Crippling Blow as AOE to make sure you don't need to chase. All of these skills provide the required mobility and the fact that they do damage AND CC to boot makes them insane. I hardly ever needed to use my AP for moving and this was usually at the end of a fight to pick off stragglers. AP is obviously much more valuable in the beginning of a fight than at the end. Add in Attack of Opportunity often finishing off enemies before they can get away. Just nutty. By contrast, I would say that my Ranger was spending more AP walking to reposition because of line of sight issues (even with a proper pre-fight setup). My Rogue in an earlier playthrough was spending more AP to reposition for backstabs. So I do disagree that a warrior needs anything other than Warfare for mobility.
Options for mages are laughable by contrast.
Just my 2 cents as someone who also thought mages were weak. In my second playthrough on tactician mode (2 char lone wolf) my mage is just destroying everything eith thunderstorm. And I really mean destroy all enemies in 1-2 turns...so I dont know. My warrior just watch the dead bodies...
Look, it's good that you can make it work, but as Sanctuary pointed out, this is late game stuff and most properly built characters breeze through everything post Driftwood. I am playing the game for the fourth time right now and there is a marked difference in difficulty between physical and magical damage builds for the reasons set out in my original post.
