Instead of the usual experimental game, perhaps we can have a quick and rapid scenario game, where each player gets 7 settlers and cannot build more. Science would be cut short accordingly. Note that having 7 and not 4 settlers will greatly increase game speed. City radius can be increased further, to make cities even more valuable. Defences of cities of size greater than 16 can be increased.
Reminds me of the one city challenge games from the old civilization 2 era.