What killed Halo's heart

Party Chat

Halo Reach's credit system

Party chat killed the communities ability to communicate and form new friendships and the credit system killed any motivation to play custom games "the heart of Halo", since you weren't unlocking cosmetics, your time was better spent in matchmaking.

That's why modern Halo has no soul anymore, the community not only lost it's voice but the social party games that brought it together have been phased out by corporate greed. The credit system to unlock cosmetics has slowly compounded to the point we have Halo Infinite's challenge system where the entire point of playing Halo, which was for fun, has been replaced with obligations to play game-modes you don't enjoy for cosmetics you don't need. This is why Halo isn't fun anymore for many people and why after finishing Halo Infinite's campaign I shelved the game indefinitely.

To further compound on the problems with the campaign, under 343/Microsoft's management the Expanded Universe has been cannibalizing the main games own story. Important events and beloved characters are dying off-screen in a book rather than in the games they represent, leaving a disjointed mess for fans who don't read those books.