Personally, I'm confident it will meet my expectations.
From a competitive standpoint, if it's as good as Reach, 343 has done their job. If it's as good as Halo 3 (and it very well could be), then they've done their job and more. The beta and the subsequent changes lead me to believe they'll do just that.
From a casual standpoint, Warzone is a MOBA-fied Big Team Battle with more players than Halo has ever seen and the full Halo sandbox to play with. Add in the gotta-catch-em-all REQ system and I think most people will have a very good time.
Campaign is far more nuanced and expectations and preferences will differ between just about everybody. It's personally the least of my concerns, but I understand that it takes top priority for many.
Ultimately, all of this is predicated on the game working and working at launch. If it doesn't, for all intents and purposes, the franchise is done. So it has to work and will work.
Sales wise, I don't care as long as it makes enough to support the team while they work on DLC and get to make another one. If the competitive community takes to the game like most expect them to, the game will have legs for a long time to come whether sales with casual gamers are great or not.