The problem of fort types

[thejeff]

Right, the good forts are only marginally better. By far the most important feature of a fort, is that you can build your national mages and troops there. Second that you have at least one turn's protection from raiders.

Everything beyond that, more admin, more defense, is nice, but only a minor improvement. If the upgrade idea was implemented, I'd be tempted to upgrade occasionally if the upgrade was only a turn and maybe 100 gold. Otherwise, just save the money for another fort.