Got my 15 wins with Azorius control too (actually UW splash black). Never felt like I needed to swap. Compared to modulo's list, I had something like:
- Warrant//Warden (okay, I had this in my list in the 15 wins, but it felt like one of the weaker cards)
- Blink of an Eye (what's the point of this card? It's just a bad cycler)
- Jace (for a UUU card, the effect just isn't powerful enough)
- Search for Azcanta (seems like there aren't enough instants & sorceries to reliably hit)
- Thought Collapse (a weak counterspell)
- Ixalan's Binding (considering it's singletone, this card does literally nothing better than Conclave Tribunal)
- Karn (not high enough impact)
- Angel of Grace (didn't feel powerful enough)
- Azor, the Lawbringer (same as above)
- Commence the Endgame (too slow)
- Nezahal (unnecessary)
+ Sphinx of Foresight (whatever else it may be, it's a 4-mana 4/4 flyer that generates value every turn)
+ Kefnet (same as above, it's a 4-mana 4/5 flyer)
+ Kasmina (too good to not run imo)
+ Conclave Tribunal (replacing Ixalan's Binding)
+ The Immortal Sun (because why not?)
+ Ethereal Absolution (the reason for the black splash. This together with TIS are unbeatable limited bombs, and this format is half limited)
+ Dovin, Grand Arbiter (too powerful to not run imo)
+ Essence Capture (because why not?)
+ Elite Guardmage (wasn't spectacular, but solidly useful)
+ Mass Manipulation (this might have been too ambitious)
+ Entrancing Melody (superb against creatures, and virtually everyone has creatures)
+ Finale of Revelation (much better as a draw spell than Commence the Endgame)
With 26 lands. Single color decks I think are subpar; you can easily afford two colors and you're going to find stronger cards elsewhere given the card pool.
When all's said and done I think it's fair to say that Singleton is the REAL War of the Mythics. Jam all the mythics & rares you got, see what comes out.
I'm a few wins off still, but haven't had tons of time to play. I'm like 12-1 or something with my list.
I can see cutting Thought Collapse and Azor, though I have yet to draw and play the latter funnily enough. Also, I can definitely see running Entrancing Melody; Mass Manip I do think is too taxing on the manabase though.
Your changes definitely signify an approach very differently from mine. I personally value role compression very highly, and cards like Blink of an Eye, Warrant // Warden, Commence the Endgame and (to an extent) Angel of Grace provide just that.
Meanwhile, you put more of a focus on bomb-quality cards like Mass Manip, Ethereal Absolution, The Immortal Sun and Finale of Revelation.
In that regard I'm actually very surprised that you run the sigificantly less powerful 4-mana cards (Kasmina, Elite Guardmage) over the two more powerful options (Karn, Jace).
Cutting Search must be a mistake; keep in mind that its activated ability does not only find instants/sorceries, but noncreature spells (like Narset)
Ixalan's Binding has the slightest niche over Tribunal of singlehandedly shutting down Petitioners and Rats. It's nitpicking, but I like that better than rarely costing 1 mana less.
Regarding the choice of wincons, I think that's up to personal preference by quite a bit. I don't think Absolution is worth the splash personally and I dislike The Immortal Sun in a deck with 6+ planeswalkers; but to each their own.