The main reason is the bad game mechanics killed the fun, and having a strategy-oriented gametype on top of this stategy-less game was a ridiculous farce. With its scandalous kill times and movement speed, and absolute inability to get multikills against people who are not completely new (might be fixed somewhat with the TU, I wouldn’t really know), it isn’t even fun going for an objective. In other Halos there’s the possibility of multikills from good positioning and aiming when the enemy is doing its thing.
The second reason is the maps do not promote teamwork or teammates taking roles and positions and routes (eg Zanzibar, Headlong). There are no bases on the maps (I don’t know about the new ones), just tiny little huts with no cover and no weapons. Just look at the size of the bases on Paradiso and Spire. There’s no picking up weapons and defending a corner or taking a turret (the one we have is completely useless and misplaced, unlike the turrets in other games) or sniper spot. Maps like Zealot don’t even have identifiable bases. There’s just spots on the floor where you arm the bomb.
The third reason is bad weapon choices, lines of sight, and flanking geometry do not promote individual or team movement along an infiltration route. For example, Turf had a great setup where you got your grenades and someone else got a PP and then they’d crouch on top of a box or building and you’d be around the corner watching 90 degrees another direction. Battle Creek has the Overshield for the flag guy midway through, a place where one guy would defend inside and another on top. Zanzibar had a place to put the Warthog as a special strategy. Reach offers nothing.
In particular, the lack of weapons or vertical gameplay (which I am glad 343i are fixing) means there’s no advantages to be had. Balance does not mean removing advantages, it means that they work well for an even chance to get them and recover once they are lost. Notable examples are the Sword, which was a tool used in Skirmish to get the flag and clear out bases, and now is so slow and useless to pull out that you would never use it except to camp in the corner. Before it made you a target and a protector of the guy going for the objective and you had a team responsibility with it. Also, minor weapons like PR and PP meant teammates had something to give them an edge when going for a base. Now they slow and useless and are never used and do not have a role in team play (one person taking out shields, for example) because they do not kill and it’s better to hide and run away or use AR/DMR. In Reach (and Halo 3, to a lesser extent) the non-power weapons are gimmicks. No one teammate would ever be able to help with a beam rifle or plasma launcher.
Fourth reason, for BTB (with its abysmal flat maps requiring long treks with sparse cover to even see enemies), is weapons are killing machines and nothing more. Banshees are not used to secure an objective except for racking up kills. Ghosts don’t even have a place in the game.
Fifth, there is no room for second-half play for CTF. If you get your hands on the flag on the excuse for a map Countdown pretends to be, it’s gone. If you have it in Hemmorhage, round’s over. Contrast with the frenzy of teleporters and desperate Snipers and teammates taking Warthogs and Banshees along separate paths to recover the flag on Containment.
Another reason is there is no room for weapon roles or movement because of no ammo or ammo pickups. For example, it was part of the game on Blood Gulch to have a Sniper. Now the thing spawns every 10 minutes with 2 shots so it’s not even part of the game. There’s no ability to go for no rockets on Reflection.
Another reason is the spawning system, which is the most terrible I’ve ever seen. I must note how much it kills the fun of having a Sniper Rifle on Hemmorhage. No longer can you lead an offense. Again, with the wrong idea of balance in mind, since it was already good and well that you were a big target for having the gun.
Nothing in Reach encourages offense or going forward. It promotes being a turtle and getting one-by-one kills. In fact, it’s necessary. There needs to be forward movement.
Quick solutions: fix everything wrong with movement and kill times, litter routes with weapons and pickups, make vehicles less destructive, have actual bases. And vertical play: there was nothing more fun than taking out enemies rushing a position from a slightly elevated position with good lines of sight to a range of incoming routes, which is somehow absent in all of Reach’s maps. Then the game might be enjoyable as previous Halos for objective games. The gist is they were particularly fun for demonstrating clever team coordination across and around an interesting terrain with strategic movement choices, and they allowed for multikills from streams or groups of enemies moving to your position in a predictable way. These two things need to be the focus if the franchise is going to be revitalized, and I think they should look to games like Team Fortress for ideas.