Though, imo, they all did go all out when fighting (except Harribell, yeah). You said that it'd be a huge disappointment if Starrk's powers just end there, but define 'there'. Being able to segregate their souls, and control them separately in battle, that, in essence, is very powerful already. The wolves cannot be damaged (according to the manga), they move at a relatively fast speed, and the explosion power is enormous. Though that leaves us wondering why he didn't use his wolves while fighting Kyouraku. I know the anime puts it like Kyouraku first eliminated all the wolves before going at Starrk, but this wan't confirmed in the manga. And while you mention that
Kyouraku himself managed to beat Starrk, with only his Shikai. From what Hitsugaya told us, Vasto Lorde should be stronger than a Captain, so an Arrancarised one (Starrk is obviously a Vasto Lorde) should be even stronger than that, yet Shunsui beat him while not even going Bankai. If that was all of his powers, then he is a big dispappointment.
I might argue that Kyouraku's shikai, in return, has very unique and strong powers (turning children's game to reality?) so it's probable that his shikai is even more powerful than some other's bankai, and his bankai could be relatively weaker (especially when Ukitake warned him not to use it where everyone can see - it could have adverse effects on the others or on Kyouraku's power, who knows.) Furthermore, his shikai Irooni game - he was wearing mostly black, so it's only plausible that he could cause a fatal strike while playing that game, no? It's a unique ability that has a very strong possibility of causing high-level injury to
anyone, so yeah.
About the Vasto Lorde thing, we do not know whether Hitsugaya said that about Captains in general or just referring to himself. I doubt that a VL could be stronger than any of the older Captains (Ukitake, were he not sick, Shunsui, Unohana (8D) and Yamamoto) They might be just on par with the other captains (Soi Fon, Byakuya, Kenpachi, etc) and they could _only_ be stronger than only Hitsugaya, since he's a pretty junior captain.
Then: Zommari. I don't think I agree with your definition/assumption that "the Espadas are ranked by who can beat who, and not just in raw power". Consider the case of Starrk-Barragan. Starrk
could possibly injure Barragan, given that his wolves move fast enough to explode in on him before Barragan manages to age them away, but that would be all. I mean, Soi Fon's Jakuho Raikoben -
which was strong enough to crack Hachi's Gate of Four Beasts - only dented his face. In the end, he was killed by his own power - which Hachi backfires on him with
Kido. Since the Arrancar don't have Kido, how could they defeat Barragan? Another one would be Zommari-Nnoitra. Zommari is the fastest Espada (or so he claims). While so, he could move far enough from Nnoitra for his release - and after that, would Nnoitra be able to beat Zommari? I doubt it - since so far, the only power of Nnoitra that we know is his strength, and strength alone.
I'd still like to base the Espada rank on raw power~ I mean,
Starrk caused death to a mountain of Hollow before he depressed his power, while Barragan did not, did he?
I missed out Aaroniero.
And yes, he, too, has, imo, release his whole power. I know that he said that he had consumed a lot of Hollow, but then, the _only_ Hollow with special power he might have consumed could only be Metascasia (sp?). He's a Gillian, which renders the idea of him consuming a Hollow of greater rank than himself (Adjuchas) a bit... unbelievable. So far, I've been assuming that he only consumed Gillians and lower Hollows before. And the power of consuming Hollows wasn't his; it was Meta-thingy's, then he ate Meta, then he obtained Meta's ability.
