Halo CE mp sucks, the guns are all useless except the pistol, the hitboxes are bad, you have to lead shots and the pistol has random spread, spawning in the open and being insta shot by the enemy team is shit. Also halo 2 spawns suck. First spawn in BtB i literally spawn in the middle of the other team
CE Pistol only has a random spread if you hold the trigger down. It's pinpoint accurate if you pull the trigger for every shot. Shotgun, Plasma Rifle, AR and Plasma Pistol are far from useless, just situational. Pistol can be used in all situations and handle itself, it's a utility weapon that gives you a fighting chance against Rockets and Sniper, and allows you to win the CQC battles versus the close range weapons, so long as you land your shots.
CE Hitboxes are extremely strict, and the shoddy Gamespy netcode doesn't translate well to those unforgiving, yet fair hitboxes. Playing CE online has its own learning curve, and it's a moving target depending on the host. So unless you play it A LOT, and pay attention to the different connections and how it is affecting your shots, you're gonna have a tough time.