Ok with what we have currently with, Talth, Toxics, and data optimizer, (and depending how you want to view it thraki ect) and planet size boosters (melters ect) and LM that grant us invincible planets, it is well within players ability to make invincible x22 planets (if you count invisible as invincible then even easier) With this in mind a x13 massive planet is hardly "broken" or OP even at its best it is only x20 VM. Most of us likely have better planets then our mission exotic. So why not to help make dan alittle money, make the mission exotic repeatable or daily repeatable? more money for dan and not "over powered"

If that were the case, I could make 3 right now from terraformers on hand just from NPCing.

I think it would be a bit overpowered, even if it didn't have the invincibility flag, as it would cut down on the number of terraformers you need to get to 13x for anything less than 2x Mega Rich.

Horrible idea. Mawks device is limited by how often you get it and what shifts you run on mawks.
Your also ignoring the fact that to produce a incinvible planet you must roll mawks 4 times with you on task 2 crew, assuming a 50 member participation rate thats 5 rolls. So your likely to get maybe 2, possibly 3 sets per year if your lucky. what your talking about is 10 terraformers, thats what 4-5 hours npcing, to make a planet that will not need cloaking or any defending and can go pp for easily 1-2k. much more if you build it right.
Just because you are able to build invincible worlds doesnt mean that it should be made easier

make it cost 10 quasi's and 10 terra formers and it only gets 8k passive cloak no other bonus's maybe that would work but other then that i agree it to easy to make and then there are players who can make 10 to 20 planets with out even thinking about it with 10 terraformers

more rifts would be more likely though as they would need GP or major amounts of work to get more rifts. mission exotics are easier to get and more prone to abusing the system

just my 2 cents

Make the rifts repeatable but require 20 quasi for each rift transformer. The originals required 10 each so that's doubling it...Maybe even 30 quasi....

That doesn't seem like a bad alternative, make em all repeatable but double up the costs each time,

Keep the costs the same , but limit it to once a year or every 6 months

Once a year seems fine enough for me.