I'm not sad to see them go. They were a vast mistake, a revolution that should have been put down. I grew up with C&C, Red Alert, Starcraft. Age of Empires was, compared to these classics, quite poorly designed and thought out. The mechanics were obscenely simple for what they were attempting to cover. The unit cap was insultingly, stupidly small, both on its own and again for what they were attempting to cover. All it had going for it was that it was 3D, and it was really very good 3D at that. Other titles in the series were better but never really recovered from all the damage the first one did. Having followed Halo Wars fairly closely, it doesn't seem it's going to do any better, just tack on successful elements from other games in an attempt to shore itself up.
Let them die. Success does not equal compentence, or good games.