could this be handled more efficiently?

Yes.

I'm really happy that you've changed your mind, because I've proposed this several months ago, but you haven't "seen a need or usefulness".

Here's the proposed flexible, easy managable, open for future extending structure:

<event>
├ Incoming
├ [Epics]
├ <event>-<year>
│ ├ Incoming
│ ├ [Epics]
│ ├ Organization
│ │ ├ Incoming
│ │ ├ <columns>
│ │ ├ <as>
│ │ └ <needed>
│ └ Proposals
│ ├ Incoming
│ ├ <columns>
│ ├ <as>
│ └ <needed>
└ <event>-<anotheryear>
├ Incoming
├ [Epics]
├ Organization
│ ├ Incoming
│ ├ <columns>
│ ├ <as>
│ └ <needed>
└ Proposals
├ Incoming
├ <columns>
├ <as>
└ <needed>
etc...
[] - optional column if applicable

Usable for any kind of event. Hackathons, DevSummits, GSoCs, Code-Ins, Outreachys, Wikimanias, ...

"Proposals" can be named "Sessions" for conpherence-like events to be yet more general, descriptive and flexible, then the structure would be for instance

Sessions
├ Incoming
├ Proposals to review
├ Approved proposals
├ Rejected proposals
├ Needs scheduling
└ Scheduled

(Of course the breakdown can be more or less granular than this, this is just an illustrational example.)

(No need to worry about creation, I'm ready to create the entire structure once the discussion is done)

Alright, so taking the Summit as an example, now we would create a projects Wikimedia-Developer-Summit and then a milestone WDS-2017, right? I am fine with this.

@Qgil: If we create a generic (year-less) project and a 2017 milestone (as proposed), where would 2017 organization tasks end up? Asking as Milestones cannot have a sub-project child or a milestone child while Subprojects can have a subproject child or milestone child.

So I'd say 2017 should be a Subproject (instead of a Milestone) of the generic year-less project, and "organization" and "proposals" should be milestones of that subproject? (As proposed by Danny_B above.)

Good point. Yes, organization can go across editions and it is more useful to do so. Content is specific to each edition.

Before starting creation of anything, please mind the icons in the proposal.

2017 can't be a milestone, but subproject, otherwise it won't work at all.

In T142470#2536315, @Danny_B wrote:

├ <event>-<year>
│ ├ Incoming
│ ├ [Epics]
│ ├ Organization
│ │ ├ Incoming
│ │ ├ <columns>
│ │ ├ <as>
│ │ └ <needed>
│ └ Proposals
│ ├ Incoming
│ ├ <columns>
│ ├ <as>
│ └ <needed>

I don't think we need all that complexity under " <event>-<year>". Organization and potential epics can be handled at the top level. At the Year level we only need Proposals. This is why I think that milestones for years is enough.

Wooo Hoo, Thanks!

Note to myself: Those milestones aren't offered in the project dropdowns. So you can only set the "Wikimedia-Developer-Summit-2017" subprojects but not directly its milestones "Wikimedia-Developer-Summit-2017 > Organization" or "Wikimedia-Developer-Summit-2017 > Sessions".
Grmpf.

I think I made a good case to create Wikimedia-Developer-Summit-2017 as a milestone and not a subproject, and not to have any other subprojects/anything under 2017, 2018...

Did you take a different route accidentally or on purpose?