I'd like to keep city positions the same in Iberia. Unless somebody invents a way to have caravels and such sail up rivers in the mod, then Seville should stay on that hill next to the copper. Also moving Seville would completely eliminate the need for Cadiz, which I intend to continue to build. This probably doesn't need to be mentioned, but that screenshot of coast under the Guadalquivir was quite unattractive, don't you all agree? IMO Cordoba doesn't need a particularly powerful coastal city, they weren't really all that spectacular naval-ly, were they?? If we do need a big coastal city then give the region enough resources to have a big Sevilla AND Cadiz.
Of course the ideal solution is a way to allow smaller ships (galley types, caravels, carracks) the ability to traverse the river tile and get to Seville, while galleons, frigates and the like will have to come from Cadiz, as historical. That's impossible, right?
We'd need a new kind of tile, like a "large river" kind of thing, it would be able to go into oceans, as well as merge with normal rivers, it should give cities water access, but a different kind, allowing for different water buildings (it wouldn't make much sense to build a lighthouse in Seville). It could be crossed by small ships, and land units but ONLY with a road going across. Also the art for it would require that the actual stream of water go through the middle of the tile, and not the border so that the ships would actually look like they were sailing through. This kind of tile would be used for the first part of the Guadalquivir, the Thames, the Nile, and more. Also impossible, of course, but you know, just in case some really amazing modders/artists were listening...