I see him missing on some lists and think he gets forgotten. I think he's top 15 (14) he was feared in his prime and gave the sannin their monikers. Lets see what you think.
I actually liked it! He stopped himself showing that opposed to being a heartless monster he was truly a shinobi with a dream. Also, it allowed him to lose without being foddered by people he probably should have beaten.
In his prime its still hard to say because of his lack of displayed abilities.
He's deffinatly in the top 20 no matter what, but I'd venture to say he could even be in the top 10 (though taking probably the 10th spot). He gets underrated a lot
I don't know where exactly he'd go (Top 10 is a little overboard, top 20 definitely) but Hanzo was without a doubt the single strongest ninja of his time which i've made a whole thread about before.