The longest game I heard anyone playing is 6 months. I think that is pretty much time to do this. I actually made cargo hull survey ships that can go the whole map. Were talking about distant worlds is one thing I like is that they are able to reuse the same faction more than once, so I can have more factions. I like the ability to pick to many factions. They have already said that Galactic civilizations is going to be mod able. Three things I would like to see added to the modding capability.
1. The ability to add player factions.
2. The ability to have seperate available players and opponents.
3. The ability to change the size of the map.
One thing I like that was added in the ultimate edition that I like the idea is the addition of an editor. I just wish it did more.
I like the idea of a bigger tech trees as long as they are still individualized. I've stated several other tech enhancements I think are just if not more significant though.
Oh I have actually ran out of techs before. I wouldn't have a problem with tech trees that were to big to be filled. I actually will get more bored with a game that almost always has the same factions, or isn't big enough that I explore the whole thing.