I played that for the first time only a couple of years ago. It might've been your recommendation. I quite enjoyed it.
MoO and MoO2 were actually separated by 3 full years, which felt like a long time back then (especially when both Warcraft and Warcraft II were released between them), but I think that I understand your point. You're referring to how other strategy games (like X-COM, MoM and Transport Tycoon) still haven't been surpassed, while MoO was surpassed only 3 years later. Yeah, I guess, in the context of game of the year candidates, that's pretty quick. Never mind.
I'll likely vote for DOOM, as well. I kind of hate voting for such a shallow game, but that shallow game was so much fun and a true game changer.