Pro tip: There is a difficulty option to remove the inflated stats of the monsters in the game, keeping the other difficulty options, something that makes the "bloat gets ridiculous" a moot point.
nevertheless, as said above, kineticists, alchemists and many spells target touch AC, you can pick mythic feats to ignore energy resistances, using the two companions or the classes with ac debuffs, like hexes or slayer/rogue combat skills, and pilling buffs and resistances usually makes your job easier.
Some people have reported that the difficulty settings don't change the spell resistance on enemies. I'd need to test it, but if true it'd put the "just lower the difficulty" into question if it is your spellcasters who are struggling to land a spell.
As for defensive buffs, they don't always work as advertised, because some enemy abilities seem to be bugged and get through. The explanation I've seen is that they lack proper tags, e.g. a fear effect is not tagged as such.
