i3 has manual tiling by choice and it isn't necessary to port automatic tiling to i3 itself. You can make a service that utilizes i3's IPC that does that. And of course people have done so[1-3].
I'm aware of i3's IPC and those tools are not even close to getting back to a normal XMonad workflow. Again, I think the layout models are different enough between the two projects that it would not be possible to build XMonad's auto layouts in i3.
[1]: https://github.com/olemartinorg/i3-alternating-layout [2]: https://github.com/chmln/i3-auto-layout [3]: https://github.com/nwg-piotr/autotiling