I agree with most of the problems but not with the suggested fixes.
Resistances - I would advocate for adding physical resistance and very high dodge to a number of mobs instead. They should be pretty common (as common as elemental ones). You should not be able to fireball or chop everything to death maxing 1 skill and stat. If you don't have the tools, your fault. Add physically immune enemies as well (on tactician at least).
Attacks of opportunity - tbh never felt like this way a problem and mages also have some positioning tools like teleport or netherswap (or you can spare a couple of points and learn anything you want from physical schools)
Nerf physical - very much agree, the damage stacking on physical is obscene and while it's ok earlygame, scaling needs to be adjusted
Meld physical and magical armor into 1 - tbh I'm not a fan of how current system ended up in general, but merging armor types is a very radical change, so highly unlikely, and I doubt it would solve actual problems. I'm ok with having mobs that are better to fight with elemental and mobs that are better to fight with physical, as long as mobs also have physical resists, beacuse currently due to resists physical is often massively better even against mobs with high phys armor anyway.
MadDemiurg mirrors my feelings exactly. The problem is the lack of counters used against physical damage in the encounters. That and the multiplicative scaling of warfare make physical characters vastly more powerful in virtually every encounter. Some characters should be knockdown immune and many many more should have some amount of physical resistance (ghosts, slimes, heavily armored, etc)
Adding friendly fire to some or all of the physical skills should also be considered. It doesn't make any sense that smashing an area leaves friendlies unscathed.
By contrast, the enemies should almost always have an elemental weakness that gives someone on your team a time to shine. This comes up occasionally, but infrequent enough that going pure physical is clearly optimal.
