Speaking of roads having negative effects in Civ 5, I think it's odd to actually reduce production and wealth on tiles with roads. If anything they should enhance production and wealth in their tiles, since connectivity makes it easier for farmers, traders and industry to reach their destination. I understand they might want to remove the tangled mass of roads and railways, but giving them negative effects isn't the best solution imo.
Maybe they should add distinct types of roads.
One basic "spammable" and less eye catching(think smaller textures) road improvement that is used to make your domain in general more accesible. This way you can move faster through your nation than usual but it won't uglify and dominate the view of your empire like it does now.
The other is type of road, the "improved" version of the standard road, this could be railroads, highways or maglev connections depending on era for instance. This type of road is not spammable and is used to connect your cities/strategic locations, just like in real life railroads and highways only run between major cities. Improved roads could grant bonusses to trade to connected cities, but they should not grant production/wealth bonusses in order to reduce the need for spamming. Some mechanic could be added to make sure the player would only want an efficient spider web like network of these roads between their cities.