As the socio-political system is a highlight of the game, I believe that inventing a marketable title for the guilds would be great, or for the cities. Something that looks like real-world titles with floating values that depend on guild efficiency and player acceptance. The more success a guild, or city, or both, can achieve, the greater the valorization of its title, and the holder of this title can obtain some advantages between the guilds or cities. This title can be converted into resources, at points of knowledge, in favors of the guild or city in question, in currency, anything, and can be tradable in the markets. The title holder should not necessarily be linked to the guild or city that launched the title, the holder may be part of one, and flirt with the other, increasing exponentially the possibilities. I think something like that would make things hot, without the need for a direct confrontation with swords and spells.
