+1 . an initial look at your decklist got me confused but after reading your detailed description, I sincerely find it unique and enjoyable! As a fellow Azusa player, I have a couple of ideas I wanted to run by you.

Boundless Realms - Ramp and deck thinning, landfall effects (scute), etc...while i understand you are trying to keep the average cmc lower as to make it more competitive, I believe this warrants a spot as it "doubles" your mana without the risk of mana reflection for example

Scapeshift - Similar to above and facilitates landfall (ex: field of the dead), titania , etc... scute

Why no Genesis wave or sol ring, because of teeg and collector ouphe? I read your description but I feel sol ring is usually very helpful and almost always the best turn 1 play

rude awakening - This card is great with nykthos, ashaya , a ritual, a wincon, all in 1. (Imagine Cradle, if only). Not to mention that it can be part of a combo ....

Rude Awakening + Eternal Witness + Kogla, the Titan Ape - First and foremost, it acts as artifact + creature removal, has survivability through 3 humans in the deck + commander, most notably being eternal witness. Using the 3, you get infinite mana. Rude awakening untap all your lands, eternal witness get back rude awakening and recast, kogla to return eternal witness.

Petrified Field - Synergy with realms uncharted, recursion of important utility lands, synergy with titania.

Regal Force - Tooth and nail synergy with avenger + titiania + scute

Garruk, Primal Hunter - I like him, he's not necessary but a solid card. He adds devotion for nykthos which may or not be an issue for your mana base. He provides a solid blocker which he can utilize his second ability on. He's a permanent version of soul's majesty at his worst. Ult is rarely relevant

Castle Garenbrig - Swap a forest or unimpactful nonbasic land.

Sensei's Divining Top - Set up topdeck with oracle, courser, augur, kozilek distortion, instant spell top deck (or you have flash, digging 3 cards is powerful even more so). If you are worried about bane or collector, just put it back on top and draw a card.

How have the following cards worked out for you....

Elvish Aberration - Expensive ramp or forest search in a pinch? Doesnt seem worth it

Panglacial Wurm - How many times have you cracked the fetch mid combat, thats so funny. Always bluffing, I like that. Aside from seedborn muse, how often do you have 7 mana to cast him? I feel 7 mana would be better spent on boundless realms for example. I understand the searchabiltiy factor is cool, but is it not overcosted?

Shigeki, Jukai Visionary - Super cool card, how has it been working for you? I like the second ability. Tell me more about your experience with this.

Not sure why that text above was huge, I did not mean for that to happen.

Also, Rude Awakening

Boundless Realms - This spell can only find basics which are not that plenty (especially when drained with fetches), they ETB tapped and overall it's not I'm focused on. Using it for Scute or Avenger is just overkill as I only need to crack a fetch 3 times to get 64 insects or 6/7 plants to finish the game. I'd rather play Reshape the Earth which has game ending potential on its own (Field of the Dead + 9 lands) even if it costs 2 more mana.

Scapeshift - I'm considering this but I would need to find room for mass-land returners (World Shaper) to make it more of the ramp spell than quality one. Azusa with Crucible effect may not be enough to return all sacced lands in short period. Obviously would be much better with Cradle which I don't possess though.

I've been playing Genesis Wave for a long time with great success (Turn 4-5 wins happened) and it was hard decision to cut it but I need to keep big-spells count as low as possible especially I can play combo now. As for Sol Ring I'd rather use Mana Crypt for T1 Azusa but still it gets negated by Ouphe, destroyed by Bane and doesn't trigger landfall effects.

Rude Awakening - I don't see it as part of the combo as it requires 3 parts (only 2 can be tutored for) and 11+ mana to run (which is a lot) and there are cheaper effects to untap lands. As for wincon it doesn't generate that much pressure as even 20 2/2 land-creatures can only kill one player and I'm not eager to lose any of my lands in combat.

Petrified Field - I did run it for a long time but needed to cut less important utility lands for Forests as I found myself color-hungry too many times.

Regal Force - it's definitely a powerhouse but I need to keep rigor in amount of cards in each mana slot. CMC 7 has 3 creature slots already occupied by Avenger (wincon), Hulk (combo) and Wurm (pet card). It's definitely viable for people not fond of Diune series (Shai-Hulud) or Wurms as a species ;)

Garruk, Primal Hunter - I did play him back in a days but I prefer cheaper (Life's Legacy) or repeatable (Greater Good) effects for card draw (even if I lose a creature in a process). Its ability can be weakened by killing biggest creature and Return of the Wildspeaker is better anyway.

Castle Garenbrig - it's good indeed except for occassions when I don't have Forest or a fetch in my starting hand which happens from time to time. It's obviously better with mana doublers but can be ok in my build as well. I don't have it currently but I will and test it.

Sensei's Divining Top - I've tested it already. Sure it ordered my top for Augur and friends but fetches "do" it anyway and sometimes I wished it way another card - that could ramp me for instance. I'd rather play Winding Way than it.

Elvish Aberration - I'm currently testing it. The thing is it can be cycled Turn 2 to keep the momentum for next turn Azusa and can produce infinite mana with Ashaya + Quirion combo. The second one didn't happen yet but it's possible. Anyway this slot is still interchangeable as there are so many 6 CMC creatures to use in a deck that finding a perfect one is hard. It can be Duplicant, Ulvenwald Hydra, Kogla, Sweet-Gum Recluse or even Orchard Strider as long as it won't clog a hand and can be tutor target in some occassions.

Panglacial Wurm - It's a pet card of mine and effective one to boot. Combat trick/End Step fatty is one option but more often than not it's used for power-matter draw effects. Mana flood is not that scary when you can cast it from library by cracking a fetch. Bonus points for Shai-Hulud esque.

Shigeki, Jukai Visionary - it's perfect T2 play before T3 Azusa and can be used right after dropping 2 bonus lands to ramp. Channel ability is super useful even if little costly.

Boundless Realms - You are correct, I did not realize your low basic count.

Scapeshift - Honestly, I use this mostly for field + yavimaya + eyes, basically a land tutor with potential landfall and land exit synergy. While its not as powerful given you don't have cradle, I believe it is still worth it if you run a landmatters build. While you view yours as a combo, I understand your reluctance.

Regarding G-Wave, I took your advice into consideration into my own build and it has been testing well. Thank you for that, I'm definitely inclined to agree with your assessment. Further testing will be needed.

Rude Awakening - Interesting assessment..... without cradle, I'm inclined to agree. That being said, its less "I want to tutor for this combo" vs. This synergizes well with my deck + has the potential to combo. I get your point though, Rude Awakening on it's own isn't that crazy, especially as an alt-wincon you don't want to lose lands.

Petrefied Field - I figure it could be useful recursion, especially with realms uncharted. But if you feel your slots are low, you know best.

Regal Force / Garruk Primal - Starting to agree with you on it

Castle Garenbrig - I would swap out one of the 2 green cycling lands for it. Both produce green but ramp IMO is more important than cycling. Especially given how land is useful even late game. The cycling lands are rarely (if at all) played in combo lists.

Sensei's - I get you, I've had times I wanted a card too. But luckily it allows me to dig three cards deeper, into usually a draw source (to draw back and recast top) or a tutor spell (which shuffled the library anyways) and I get what I need then and there. Not to mention kozilek distortion synergy is really strong + you have 3 topdeck matters cards. I respect your decision regardless.

Shigeki, Jukai Visionary- Which do you find more useful, its 1st ability or channel? Please tell me more about how channel in particular has been working or not for you. I'm super interested in it

I wouldn't swap any cyclers for Castle as they play important role in a deck. You see I made Azusa to play as a tempo deck where every turn matters. Cyclers are T1 or T2 plays which can be returned with Loam to draw more cards or reanimated with Crucible effects. Shigeki is T2 play which ramps turn later and returns something (usually 2-3 cards depending on boardstate and hand) later on. I think its first ability is better as I can use it more times by replaying him especially when I have more important stuff in hand to use mana for.

Getting back to Petrified Field I think it's less important the more land-return effects we play. I use 3 of them currently (not counting Witness and Shigeki) and there is Ancient Greenwarden to try although I found him clumsy and unnecessary most of the time (and it's a nombo with lands like Lotus Field and Glacial Chasm).