The Quasar Sturdy is more viable than Mold Breaker simply because Sawk doesn't need Mold Breaker to hit everything it needs to with equally little risk, whereas Sturdy gives Sawk the chance to punch a hole into anything regardless of whether or not the target is faster; maintaining Sturdy is also easier in this meta due to the better hazard removal. I don't know where you got the impression that Close Combat's defense drops count as "risks" to Sawk when it's not a mon that is even supposed to be taking hits in the first place (like Primeape and
unlike Hariyama), not to mention Sturdy alleviates those concerns. I've no idea why you talked about Mold Breaker EQ hitting Cryogonal, Lanturn, and Pyroar in one fell swoop when Close Combat already butchers the lot; you even put Life Orb in your calcs so your argument about "not using Close Combat to preserve defenses" goes out of the window already. To get to the point, Earthquake is less useful than Stone Edge on Sawk since Zen Headbutt already hits every Poison-type Earthquake wants to hit (while also hitting Vileplume which EQ misses out on), making EQ a redundant coverage move outside of not making contact with Garbodor to preserve Sturdy (and again, you're using Life Orb), whereas Stone Edge lets Sawk power through bulky Flying-types which it could not before, such as Eviolite Scyther, defensive Rotom-S, and Pelipper, although Stealth Rock alone puts pressure on them as is.
Traits: With 125 base Attack coupled with 120 BP STAB and the ability to hold an item (unlike Archeops),
Sawk's raw damage output is easily one of the greatest in the entire tier. It also has a 85 base Speed stat, which is significantly high for a Pokemon which hits that insanely hard; this means
Sawk easily has the potential to define its Speed tier. Sawk even possesses fairly flawless coverage: between Close Combat, Knock Off, Zen Headbutt, and Stone Edge, with
virtually nothing in the tier bar Granbull is truly safe from Sawk's blows, while also being the biggest reason why Psychic-types carry Colbur Berry. Even its abilities are useful to it, though Mold Breaker much less so these days; Sturdy on the other hand gives Sawk at least one hit against anything if you can keep it intact, and not many mons enjoy taking hits from Sawk.
Trends: Sawk is undoubtedly one of the biggest benefactors of the meta shift. The departure of Fletchinder and Uxie and the arrival of Skuntank and Shiftry are nothing but good news for Sawk. The addition of Shiftry, as well as the fact that Uxie users are expected to resort to Mesprit, mean that the 80 base Speed tier is becoming more crowded, making
Jolly Sawk more usable than before. Sawk doesn't particularly mind the loss in raw strength either, since it now has partners that can easily compensate for it and facilitate its destructive prowess. Skuntank can Pursuit trap basically all the Psychic-types in the tier (or play mindgames with Taunt against Baton Pass Musharna), and between Skunk's Pursuit and Sawk's Knock Off, the Psychic-types Colbur Berry is hardly expected to stay long enough to sufficiently keep Sawk in check. Shiftry on the other hand has access to Defog to help keep Sawk's Sturdy intact, and can lure out bulky Poison-types to soften them up for Sawk, especially if Shiftry has Extrasensory. This powerful support make it ridiculously easy for Sawk to break teams with minimal risk to itself. What Sawk is most expected to run probably depends on the current metagame trends;
if bulky Flying-types such as Pelipper and Rotom-S start seeing more use, then Sawk would probably just keep Choice Band to hammer stuff as hard as it possibly can, especially since the Flying-types have a much harder time keeping CB Sawk at bay if Stealth Rock is in play.
If bulky Flying-types don't see as much play, Sawk can afford to drop Stone Edge and mix it up with Black Belt or Expert Belt, and/or even pack Taunt in order to mess with bulky mons even further by preventing status moves, such as Thunder Wave, Baton Pass, Will-O-Wisp, or recovery on your switch-in; Sawk can even attempt to beat Gourgeist 1v1 this way.
Thoughts: On one hand, it's not just Sawk that has received a boon in this meta; literally all the Fighting-type Pokemon in the tier receive a substantial buff to their effectiveness. However, Sawk is unarguably the most offensively potent of the available Fighting mons due to its sheer power, good Speed tier, and a very capable movepool (which gives additional versatility which it frankly doesn't even need D:), thus allowing it to make the most devastating use of that support. The only thing holding Sawk back is that its counters and responses have good longevity, or in Garbodor's case can whittle away at Sawk to compensate for its lack of recovery. Sawk is definitely far from overrated in this meta, as with its newfound support it has become one of the easiest / low-risk-high-reward Pokemon to use right now.