**EDIT2: Ok, I used him to clear some of the low-to-mid-level Descend Challenge tiers. Yes, he's powerful. But he still NEEDS skilled-up monsters to be functional, more than other leads I've used. Something to work on!

EDIT: TL;DR: FIRST OFF I AM NOT SAYING AYOMI SUCKS.
With what everyone says, it looks like I'm right that skilling Z8 and AHaku are the biggest things holding the team back. It needs constant orbs, clearly, and to have the hastes up more often – without max skill I hit long dry spells of just-five-orbs or sometimes less, while the other teams I mention already have their orb-change flows largely skilled up. I'd change my characterization now to say AYomi seems much harder to get going than other teams, mostly because of Z8.**
...

I have two accounts, run several teams – the leads are pretty similar on both accounts, though the subs switch out.
I run Urd/AShiva and AShiva/AShiva teams, both are great, tons of power and functionality.
I run ALakshmi teams, both a row-based and a prong-based (one has better prong subs, though row is better, but I'm working on transitioning), both are great, tons of power, solid function.
I run Verd/Bastet and Bastet/Bastet teams, both are pretty solid and not too tough (though I really prefer to run Bastet/Bastet on 7x6 boards to improve my chances).
I've run LKali/LKali teams and ASakuya/ASakuya teams (rarely, but sometimes), and they're pretty solid.
But dark teams? I understand that they're supposed to be super great, but I'm just not managing to be very blown away by them. And from what I understand, I have pretty great subs for them, so I don't know what I'm missing here.
I'm trying to remember off the top of my head, but my main team for AYomi is typically AYomi/Z8/Haku/BeachPanda/Satsuki with an AYomi or Yomidra friend. All are max level.
Now I will say my first thought would be that I don't have Z8, Haku or BeachPanda skilled at all yet (working on it - AYomi and Satsuki are max-skilled), and I don't have much plusses in them.
But even just messing around with the team in lower-level stuff where I don't have to worry, when all my skills DO get up I'm pretty underwhelmed by the burst itself, and by the general damage between bursts. I make the 7-combo let's say 60-70% of the time, which could use some work, but still. I can manage similar damage levels or better much more consistently with AShiva and Bastet – and yes, they can get color-halved damage, but when they're doing more and doing it more easily it makes up for it, in my book.
My initial guess would be that Z8 and his increased skyfall getting skilled up would make a lot of difference – but is there something else about this team that I'm lacking?
I feel the same disappointment in ALucifer and APanda right now, but those teams lack a bit more in levels and have the same skill/plus issues, so I'm not worried about that so much.
My alt's AYomi team is AYomi/Z8/DValk/Okuni/UVOPanda (will be UUVO when it comes – I have an APanda but wanted the God type for pairing with Yomidra).
Other available subs from the sub's guide include: Main - DValk, DIza (would need a lot of work), 2 more Satsuki, DKali, AAnubis, Akechi, DMeta, AHades, Dill Sirius, Grisar, Lumiel, Hanzo, CDK and some of the other trash-tier subs.
Alt - DIza (would need a lot of work), DKali, AAnubis, Persephone, HIza, Castor, Akechi, DMeta, Grisar, Lumiel, Hanzo, CDK and some of the other trash-tier subs.
Thanks for any help – I know he's supposed to be great, I'm just trying to see it!