i liked the campaign it was fun and braindead the story was lame but nothing has been good since halo 2 only exception is odst, it was atleast better than halos 4-5 and reach.
the open world is pretty fun solely because of the grappling hook and I think the format works well with halo but co-op should have been in since day 1 to really elevate the game, playing as your multiplayer goon in the world should have been a feature, just seems like 343 is really good at stretching the development of games over like 7 years to add nothing.
i think conceptually the multiplayer is great and the forge is awesome now that it's in the game but there is nobody playing this game and the amount of weapons in the game has not changed since launch, the armor coatings wouldn't be that bad if there were alot of them and alot of ways to unlock them or buy them but there's like 12 total and half of them are locked to a battlepass