Geo, while the system doesn't currently track CDs when the player is replaced, it should. If changes were to be made in this area, that should be the first one. That then allows further changes on top of that. So the fact that it currently doesn't should be used as an argument against making certain changes.
Regarding the cost to buy-in, right now it is setup so that after your points are added to the pot, your new country's value will match your buy-in. While mathematically logical, it isn't socially logical. A 1 center country isn't worth 1/34th
On the one hand, you could make CD takeovers cost nothing, but also gain you nothing point-wise and GR-wise. But that might encourage people to just go in and mess with things, or even specifically mess with someone that annoyed them in another game. Especially for larger countries being taken over.
So maybe just adjust the buy-in amount so the further below average size, the less it costs. A buy-in at average size or higher would cost the normal amount. If the size is less than average, divide the buy-in by the difference. So with three 11 center countries and one 1 center country, divide the buy-in by 8.5.
As for auto-draw on CD, that certainly doesn't seem workable. Better to allow an option where the game auto-extends the phase on the first NMR and auto-pauses on the second NMR and puts the country in CD. Then the player can be replaced or the game drawn or cancelled. If the CD player comes back but then tries to hold the game hostage when everyone else is ready to go on, a mod could restart the game since the pause was due to the CD.