I loved so many of the features mentioned above. For me, another favorite was Base Building, and the Architect mission options. Also, the Ski Chalet, yet another great place to gather and RP, plus skiing! I loved the Holiday events, and especially frozen Croatoa where you could ice-skate. So many great 'quality of life' improvements the Devs were always adding. :-D
Also, I loved Devs who actually listened to what players wanted, and acted on their suggestions. Gosh, I miss this game!