I think theming bonuses could use a pass. Every now and again you find one and its just like "+3 gold". I will compile a table, but I think we would agree that the bonuses should be around twice as good as a normal building!
P.s. Wartburg is actually slightly more culture than amphitheatre, right?
wonder theme+bonus is 10 culture, which is 3.333 per work
amphitheatre theme+bonus is 6 culture, which is 3 per work
edit: jesus christ, Golden Dragon Pagoda can go hard. +30 theming bonus with all criteria :O