As it stands right now I'm thinking it's something like;
1- Shunsui (he might be scared to piss Unohana off but to me it seems more like that's done for comedy rather than actual fear)
2- Unohana
3- Mayuri
4- Shinji
5- Kensei
6- Ukitake (the guy is pretty much always sick.. hasn't shown anything impressive yet)
7- Rose
8- Komamura
9- Soi-Fon
10- Hitsugaya
Both Kenpachi and Byakuya are not able to fight at the moment so they're not included.
Why did I put Mayuri third? He's got intel on all the captains, he knows their strengths and weaknesses and pretty much always comes prepared. Sure he lost to Ishida but let's not forget the immense power boost Ishida got when breaking his glove (there's no telling where he'd scale in that form). Shinji and Kensei both rank high due to their hollow form but also their shikai alone is pretty badass (Kensei has shown his Bankai but except for that huge explosion we don't exactly know how or what it does).
Ukitake is pretty much always sickly and can't fight at full strength, his fight against hollowfied Shiba Kaien made him look weak aswel. Rose hasn't shown that many impressive things either but I still rate him a tad below Ukitake due to his hollow form. His shikai however... I can't see that many people getting caught by that really.
As for Komamura, Soi-Fon and Hitsugaya... they don't know how Komamura's Bankai works (assumingly they don't) and because of that I think he'd beat them. Sure Soi-Fon has her speed but we say Komamura's Bankai can swing fast enough to hit a hollowfied Tosen which should be around her speed. Soi-Fon's Bankai can also be easily avoided (assuming it's not a heat seaking missile

). Hitsugaya altho a fan favourite is just... he's still young and acts rashly, he constantly makes stupid decisions and gets himself hurt way too early in fights..
Oh and.. god I hope Renji doesn't get some new powers

wish Kubo would just stop drawing him really. He's such a useless character and pretty much doesn't serve any purpose except the occasional rescue of Rukia. I do remember thinking Zabimaru was a pretty cool sword but his Bankai... never liked it.
Oh and did anyone else notice Kubo just keeps drawing Ichigo in his bankai mode when he ain't even fighting anymore, whats the deal man?