lightnica: Exile 1-3 are Win16 games. Do to decisions on Microsoft's part, Win16 games will not run on a 64 bit Microsoft operating system. GOG does not have a work around for this yet at least. I would not expect to see them here on GOG.
You can get Exile 1-3 on a CD for $15 + shipping direct from Spiderweb these days. If you phoned/emailed them you could likely talk them out of the CD part, and consequently the shipping. (You would need to have installed the games and give them the registration numbers.)
Blades of Exile was made open source and ported to Win32. The project page is
here. So Blades of Exile is available for free and works on 64 bit Microsoft operating systems.
It would be rather impressive if some recreated Exile 1-3 as scenarios in Blades of Exile. It would be very time consuming though and Spiderweb might make a stink.
Avernum 4-6 are on Steam (and available for $4 at the moment via
an indie sale) as I would expect to see them on GOG too.
Apparently there was some problem with Avernum 1-3 that kept them off Steam. I suspect GOG will have a look at that and we may see Avernum 1-3 on here as well.
Additionally, considering the prices Spiderweb has been accepting on Steam, we might see Avernum: Escape The Pit, Avadon: The Black Fortress, and maybe Nethergate.
I would say that if i were jeff, i would test the waters and put avernum 1-3 onto gog. That way its easier chance of success and then he can release avernum4-6 when thats done. I would do exile last, but thats just me.
To be completely honest, im not really sure which is better regarding exile and avernum. Some people swear by avernum and i can see that. But just as many people swear by exile. Many people really like nethergate but it sold bad. Very strange.