They're optional.
The Martial consolidations are to make room for things like Swordplay Upset or the Shield Feats that are hardly broken.
I guess save or die ended up being too much of a thing if you stacked enough DCs?
Yeah, I know.
Thing is, martial DPS are already very strong, reliable and have good progression. They also don't have to manage as much stuff as casters, just buff up and go ham. Casters have to account for spell slots, spell resistance, energy resistance, various saves, immunities and friendly fire. Just saying, you know this better than me. Spell focus + greater spell focus + spell penetration + greater spell penetration is insane feat tax, that simply should not exist, some casters would also need point blank shot + precise shot... I say it's these things that should be relaxed or lifted outright, martials in general get a good number of bonus feats, but, because of the said things, casters are usually feat starved.
Can't say how high you can stack DC at the moment, I'm currently running school savant arcanist, we'll see what happens once I get foretell. But if you ask me, being able to stack crazy DC is enterily justified by enemies having inflated stats. Martials running around with AC so high that they can only be hit on natural 20 and reliably 1-2 hitting even stronger enemies bothers nobody, but as soon as casters are able to reliably land their spells past spell resistance, immunities and saves it suddenly becomes a problem. No idea why.