In general, I feel that Theocratic Rule is the clear winner here...even with Tall play. The reason is WLTKD can be maintained for large stretches of the entire game...including the early game. The golden age bonus may be stronger, but its much less frequent until the late game....and yields early are always stronger than yields late. Combine that with the fact that TR works with all of your cities, not just one like DI does. Again even if you only have 5ish cities, that's a lot of yield left on the table. That aside, Theocratic rule gets a +5 culture bonus to its holy sites vs +5 faith from DI. In general I would say the culture bonus is stronger. Now granted you aren't getting tons of holy sites, but still every bit helps.