I was waiting for FE to comes out, and when it came, I was extremely rejoiced!
I did a few test games with the vanilla version, but did not go that far. Then I switched to Stormworld, using 12x8 maps (yes, that's big). 4 times in a row, my games ended up crashing (around turn 200).
I was told (with some good reasons) by Heavenfall that memory usage was just too big. So I scaled down to 8x6 games, with 8 factions. Tried that twice. Again, at some points, a repeatable crash. HF told me he was only playing on medium and had no crash with this setting.
Preferring large map with vanilla over medium map with a very good mod, I started some days ago a 7x6 map with 6 factions, vanilla.
Now is turn 132. Again, a recurring crash. (see log below, nothing indicated that sounds suspicious).
So my conclusion is that it is not possible, because the game is not stable enough, to play large maps. My specs are Windows 7 64 bits, 4 gig of RAM, a powerful video card and plenty of disk space.
Given the current settings I would have to use, i.e a game with no more than a medium map, I don't think I'll resume playing FE right now, and I'm very sad of that, because I really love the game. A pity really.
Debug Message: Current Memory Usage: 822912 KB
Debug Message: Cities in World: 39
Debug Message: Units in World: 1410
DebugMessage: AutoSaving - Begin
DebugMessage: AutoSaving - Complete
Debug Message: AI Faeryl Viconia: Now researching Glyph Stones
edit: in fact this is not pure vanilla, I'm using city snake mod, the mod that adds some spells and modified the benefits given by some buildings. Now, I guess that devs will say that as this is not a vanilla game, I have no right to complain. Somehow I think that the excuse is too easy to pull out.