I can maybe mention one or two things that might not have been completely discussed yet. My paraphrase:
Point 1:
"A player can make an attack colony anyway, so why do Nexus players think that there is a need to move their planets if a Genesis account moves their planets close to the Nexus player account planets? They should use save flight."
Well, the Dark Gate uni gave me a chance to test this. I deleted my bad Retro account and put my Dark Gate account into Retro. I did a bit of browsing around and placed all of my planets close to 2 or 3 weak farmer type players. I then farmed them for a few days until I became bored. My Retro (old Dark Gate) account is now just sleeping in VM, but for a while, one or two players possibly had a few days of less sleep than usual...
Here is the difference between what I did and how a raider account already in Nexus can move an attack base:
ALL MY PLANETS in Dark Gate were fully established with mines and teleporters etc. It cost me NOTHING to suddenly have TEN raid bases next to my targets when I merged into Retro. Now if I want to focus on a target with my Nexus account, it is very different. Suddenly I have to make a difficult choice. Do I really want to lose weeks of building PER PLANET that I delete and then colonise next to my target? Sometimes it is MONTHS of building per planet that I would have to sacrifice. For someone in NExus like Gin~Ossi I can imagine it would be YEARS of building that he would have to sacrifice.
I also cannot reasonably place ALL of my planets next to my target in a 7 day period without basically deleting my whole account's building points!! But the Genesis players CAN DO THIS.... WITHOUT any cost!
Point 2:
"What about people who just wait to the last minute to see where their targets have moved before they move. A kind of brinkmanship of who moves last gets the benefit."
Well, so what? If players want to gamble with last second moves, that is a risk they can take. If they get their timing wrong, that is their tough luck.
BUT - maybe there is another way. All Genesis players fill in a list of their choice of planet locations, but cannot move the actual planets themselves. All Nexus players get a choice of 6 (maybe more, maybe less) planets that they can move. Same thing, they choose a list of locations.
All planets get moved by the system at the same time, let's say 03:00 am. Then immediate protection for all those planets for 7 days. All timed at the same time. If more than 1 player chooses the same location, the system will put the planets on the closest empty planets. I don't know how easy that is for the system to do, but it might solve this issue. It might be interesting to see where the planets all moved to the next morning.
Just some thoughts and suggestions.