In my opinion it is very good these days. Almost all of the major problems at launch have been resolved. There's a ton of game modes and maps. They added firefight, forge, custom games, infection, and there are like 15 different playlist to choose from.
They're actively working on networking improvements (three playlists use the new netcode currently, and they're using that to test how well it works before making the whole game use it).
Cosmetics are in a much better place than at launch. There are a ton of options and a lot of things work on every armor set.
The biggest issue imo is still the battle pass system. Limited time events (like the Christmas event) replace the season pass if you don't buy the paid version, so there isn't much to unlock at a given time unless you pay. But, paid passes never expire, and you can go back and buy old passes, and most passes contain enough credits to buy another pass, so it's basically a one-ti.e fee.
If you don't like Halo, nothing has changed that will make you like it. The game plays like it did at launch in terms of gunplay and movement. But the overall experience is in a much better state than at launch
This is a fair point. Forgeable AI is pretty sweet but it's not a replacement for proper campaign expansions unfortunately