Versailles over AW - Especially after the nerf of AW. (I preferred AW in the past and i used to lose less on defense when i had AW) Of course Taj mahal and temple of tikal are relatively useless.
Forbidden City and Colosseum depends on your personal preferences. I switched to FC because of WW and i'm doing great without the strength of the gladiator. I still love colosseum equally. Of course Terra cotta and notre Dam are relatively useless.
Brandenburg Gate and statue of liberty depends on your personal preferences. I guess if you're planning to use heavy tanks or/and machine guns frequently.. 20% from gate and 15% from nation is gonna be great.
Still testing the statue of liberty. Air boost for zeppelin seems powerful but not sure yet if useful, still can't take out castle in one shot. Air boost for biplane is useful.
Kremlin is nice, but i think germans is all about offence and field domination. And of course Eiffel tower is useless, not just relatively.