That there is effectively only one tech path gets dull, and limits the usefulness of telling vassal states what to research. But given Future Tech can be researched repeatedly, why not have other techs that can be repeatedly researched further down the ladder? It'd also be useful for civs that didn't want to research a tech that would render buildings/wonders useless. Frex: Steam Punk Tech prereq: Railroad Gives: +1 rail movement, +1 Airship range. First to discover: +1 Airship Strength Chivalric Lore prereq: Guilds Gives: Stables +1 . First to discover: Mounted units get +1 xp [Religion] Tech prereq: Music, a State Religion Gives:  Monasteries additional 5% , and 5% while the State religion. First to discover: one of your cities gains the state religion Animal Breeding Tech prereq: Animal Husbandry, one pasture Gives: Pastures take -1 turn to build First to discover: Gain an animal resource to a random legal square in a bordering one of your cities Despotic Tech prereq: Slavery Gives: +1 when whipping. First to discover: A Scout unit gains 'slaver' promotion, allowing it to attack defenceless units such as workers.