There is a very high need for better interplanetary and interstellar population transfer system.

For Interplanetary: It's only possible to swap around pop stacks that fit into available slots on the planet you want to place them on. If there are no slots you can't move pops. If there is only one free slot you can only move pops one at a time. With the spaceport being a buffer of 3 slots. Which at least is something. Not enough tho. So if you manage to populate your 1st lvl system to the max (by accidentally wrong destination for migration for example) you won't be able to swap pops around at all. That's super inconvenient.

My suggestion: Add to planets a number of virtual slots equal to the maximum number of slots possible on a planet (or whatever you use for actual slots). Let the player place pops into those virtual slots. Make it so if the player performs any action other than interplanetary pop management the pop configuration reverts to the last valid one. Make it remember pop configuration the moment all virtual slots become empty.

This way it'll be possible to swap pops on planets in two moves no matter how many pops are swapped around.

For Interstellar: It's very hard to find a particular species in your empire when it gets big enough. And then it's incredibly hard to manage their pops on the Imperial level. 

What if I want to breed my Amoebas to 20 pops and then start shipping them around the empire for that sweet sweet +15% food on a System? For that I'll need to isolate them in a system (so that they are the only ones that breed there) and then I need to ship them around my systems. 

But I need to gather them first. Going system by system. Manually. And then I need to ship off the pops of that system I designated Amoeba system. Three at the time which takes a few turns (because naturally I had to develop it first, Amoebas suck at working). Again, manually. That's super inconvenient.

My suggestion: A new panel. Empire Demographic or something. In the F1 window I think. Right beside systems. List all systems, just like in systems panel. No yields, no governors, no construction, no policy indications. Just name, status, Pop/Max Pop, and species composition. As in, a row of pop icons sorted like on a planet only in system scale. So in 30 pop system there will be a row of 30 icons sorted by species. And when I take 12 of them and drop on another system it queues it up and sends them off from the space port by the number possible on its own until they all depart.

The mechanics of having significant bonuses from having many different populations in my empire are very interesting and I would love to explore them more but as it stands now, it's too bothersome to try. I would really like to see it changed.

For Interplanetary: 

CORRECTION: The pops swap around fine, if they go over the limit. For some reason during my first log into the game they didn't. On second log in they do swap.

I guess that's not important then. It's still a bit of a bother when there are more than two species on a planet, but it's not a big deal. For now.

However if the interstellar migration thing gets solved then it will be a much bigger issue because there will be a lot of systems with just one or two pops of a type.

For Interstellar: there's some really weird shit happening when a system tops off on population when there's migrants due to arrive. They seem to just hang there and do nothing. You can't even move them. And it's exploitable too. With that it's possible to fully populate a new colony and have those waiting pops instantly replace everyone sent to the new colony.

HUGE + \ UP \Second this, This right here is a major flaw.

Yep the migration system is tedious at the moment and exploitable.

You can't stop pop breeding, so you want to send 1 pop into one system (A). So you gotta take off 1 pop from the other system (B) to be able to queue up the spaceport in (A).

You do that, by the time the 1 pop gets there (B), they already bred and the system is full again so the 1 pop is stuck in outer space.

Now you gotta send another pop of the system (B) so the one from the (A) will get in.

Civilian ships are not controllable so before sending them elsewhere you have to let them in to the system they are stuck in and then resend them.

The fact that you can't stop breeding, and the fact that you need to send 1 pop to be able to queue up spaceport then send another pop to let the other get in, creates 2 pops that were swapped by 1.

In a fully developed empire it will mean there are going to be a lot of pops stranded in outer space.

Today also i did a small experiment after Ravellon pointed me to this problem.

A system that has 1 pop slot can get infinite amount of pops from other systems.

You keep queuing them up to be sent to that system with 1 pop slot, once they arrive, they just park outside in space.

Then you send a colony ship not far away from that place, and send the pops from that system and it instantly gets refilled by the guys waiting outside.

1. In my opinion, breeding should stop if that system has a designated passenger that comes from another system and his place should be reserved.

2. Civilian ships should be controllable to avoid letting them into a system so you'll be able to send them out again to another. If breeding isn't going be stopped by reserved "incoming population" status. So once they park outside, you just manually redirect them instead of going into system space port and sending the indigenous population to let the others in.

3. Population stranded in space should have an approval penalty.

I only have 8 star systems and oh boy this made my head hurt, i really hope you guys look into this, this is pretty serious since there is a heavy reliance on using system bonus on pop base.

I believe you can still drag and drop population on a full planet and it will exchange the populations (ex: you have a planet full of Sophons and you want to put 3 Haroshems on it - drag and drop the Haroshems on the Sophon planet and 3 Sophons will be placed on the planet the Haroshems are coming from)

Yes, but in my correction I also mentioned potential problem when migration will be fixed. There are bonuses for having a single pop in a system if you have 20+ of them in the empire. Which is quite possible to achieve for 3-4 types with careful breeding programs and lucky explorations. What happens when there are 5+ types of pops in a system? Swap is automatic and there is no explicit control over who gets swapped from the receiving planet. I haven't tested this out too much but the game cannot read my mind, so the swaps in this case inevitably will be not exactly what I want. Which is the purpose of UI, make the program do what the user wants it to do.

But it's a minor issue. Will be nice if it's addressed but not that big of a deal and there are more important things to do. As I see it, it will be best to take a note of it and add it to the to do list the next time you'll work on pop management on planet. Which may never happen or which may happen relatively soon.

And I'll add my suggestions to the ideas section when I formulate them better, I did not know it existed. Created account specifically for this thread.