lol Avalanche was only good in CTF and it's not even the best of the BTB maps.
Avalanche is easily one of the best designed maps in Halo 3.
-Valhalla's movement is shit due to a contested middle that becomes a giant choke point.
-Sandtrap is competitively flawed in objective playlists with asymmetric bases. It's an absolute chore to navigate on foot.
- Standoff is a cluster fuck due to its size and grenade spam in the rocky middle. It often devolved with one team quitting while the other circled the base in warthogs.
-Last Resort is okay, but a downgrade of Zanzibar, movement doesn't flow nearly as well due to the added catwalks, etc.
-Longshore is pretty great, a semi assymmetric map where no base has an overt advantage, plays well in all game types though is limited on vehicle play.
Avalanche is completely symmetric which is great for objective. It has defined vehicle and infantry lanes that give players quite a few options in navigation. Gaining a power position like the mid hill doesn't halt all map flow thanks to teleporters, vehicle lanes and man cannons. It's perfectly suited for slayer flipping spawns doesn't lead to the enemy team spawning right behind you. It's far and away the best BTB map in Halo 3 and the best in Halo period, its design works well in modern Halo as well.