When I look at the Legendary Sannin, I see a continuous combo. However, there are a few flaws from the Sannin that I've seen:

Jiraiya:
1. Ero-sennin doesn't buff Jiraiya all that much, because only Tsunade contributes to this benefit.
2. His Mystery is non-prompt, which creates a bit of an issue when working around a stun-based team.

Tsunade:
1. Her Chaos passive can be easily reflected back, especially with the prevalence of Fire Mains running around.
2. Her crit buff from her Mystery doesn't seem to create much more crit chances, therefore won't be causing much chaos spreading anyway without decent enough refines anyway.

Orochimaru:
1. His Repulse standard doesn't combo well with the Sannin's set without an appropriate pet.
2. His stats are lacking in the defensive category, so you'll be waiting for him to revive more often than not.

All in all, I'd * with your Akatsuki team, especially because you already have Konan, because you've got a more diverse amount of chases at your disposal. Coupled with the fact that Jigokudo can revive Tobi multiple times to create more havoc for your opponent is an asset that not many people can boast. :o