Striker said:
Plus there's many others in Halo 3 that had ridiculous spawning (though, I'm not sure why people harp on bad spawns; Bungie hasn't had a great spawn method for, well, ever), awful weapon placement/additions, and hidious sightlines. Or, simply, not very fun to play for slayer or flag/bomb. I'd like to list all the maps I would place below Pinnacle/Ascension, but I would just be beating a dead horse.
Well Cliffhanger/Atom are below Pinnacle in my opinion. I've played AR/pistol start on Pinnacle and it's at least tolerable.
A lot of their smaller maps from previous games aren't terrible but aren't awesome either, a lot of them have some sort of nagging flaw. Hell I'll just go through them, these are of course my opinions so feel free to be all "aww hell naw."
Halo 3
Blackout: was supposed to be lockout but grenades caught in awkward ways due to different textures.
Cold Storage: feels like a maze.
Construct: Lifts. Nothing but lifts.
Epitaph: lot of running around outside, another maze.
Foundry: Some versions of this map were well made (like ones without the back area to hide bombs/balls).
Ghost Town: another maze like map that didn't really have a central focus.
Guardian: not the fault of the map but it always had gametypes with far too many people so it ended up being cramped. Should really be 4-6 and even 6 is pushing it but certainly not 8.
High Ground: just not a well balanced map.
Isolation: Ugh. This one just had lots of issues I don't know where to start.
Narrows: Best way to describe narrows is one game right when we all spawned, I tossed a plasma all the way to the other side and stuck someone. This one actually suffers from the exact opposite of maze-issue in that it's too damn predictable where someone is coming from.
Snowbound: Shotgun camping underneath. Getting sniped/lasered on top. So fun.
That sounds like all of them from h3 but the Pit and Heretic were pretty good.
Halo 2
Ascension: Never been a fan of this power weapon control map.
Burial Mounds: I know it's not small but they always had 4v4s on this vast piece of fail anyway.
Colossus: Wasn't terrible game play wise but the spawns were god awful, especially if someone was an excellent sniper.
Desolation: meh.
Elongation: Another one that probably should have been 4-6 players instead of 8.
Foundation: Zombies was the only gametype that made sense on this map.
Gemini: Not terrible but it was one of those lulzy chaotic ones everytime I played it.
Relic: Bit too big for 4v4, yet again another one in which you were tasked with going objectives with a small number of people on a relatively large map.
The maps that worked for what they were, would be Beaver Creek, Ivory Tower, Lockout, Midship, Sanctuary, and Warlock.