Don't you think there are too few game modes? I'm not talking about Barebones etc, since they are just TDM with other settings, but the only new thing is wager matches. Why didn't they took the cut MW2 game modes?
By the way, the explanation of some gamemodes, taken by CODwiki.
Die Hard is a cut gamemode for Call of Duty: Modern Warfare 2. It is a variant of almost every other gamemode (Die Hard Team Deathmatch, Die Hard Domination, etc.). There is not much known about the Die Hard mode because it can only be played on hacked lobbies or servers.
The main feature of this mode is that the players have more chances to survive. Everyone goes into Last Stand after being shot by an enemy, even if the player's class does not contain Last Stand. While a downed player is in last stand, a teammate can revive him (a teammate in last stand is marked with a green cross). In addition, the weapons are a bit weaker than in normal game modes.
Arena is a hacked game mode in Modern Warfare 2 multiplayer. It is one of a couple hacked game modes discovered, including Global Thermonuclear War, One Flag CTF, and VIP. It is very similar to the game mode Search and Destroy. Respawning is turned off in an Arena match, and the first team to win 4 rounds wins the game. The object of the game mode is to kill all the opposing team's players; but, if there is only one person on each team left alive, a flag spawns in a random location, and if it is captured, the team that the player who captured it was on wins the round. After the flag spawns, even if one of the last two players alive kills the other, the flag must still be captured in order to win the round.
Global Thermonuclea War
Global Thermonuclear War is an insufficiently hidden multiplayer gametype in Modern Warfare 2. Each side fights to capture a Tactical Nuke in the middle of the map. Once a team has captured it, a countdown automatically starts, and lasts 40 seconds. When the countdown ends, the Nuke explodes, killing all players on the map and winning the game for the team that captured the nuke. For a team to capture the nuke, players have to be in the area around the nuke. For every second in that area, a point is given to that player's team. Once 100 points have been scored by one team the countdown begins.
While an enjoyable game mode, this mode's greatest flaw lies in the fact that many of the maps come with inbuilt advantages to one side when based around capturing the nuke. This is caused by the fact there is only one objective which is static thus tending to lead to a meat grinder with the odd flanking procedure before the need to gain ground prevents the losing team from doing anything other than throwing themselves at the objective. Global Thermonuclear War is a game mode on accessible through hacks, using a JTAG. On Rundown, the side that spawns with the building overlooking the central building will inevitably win as it is easy to launch grenades to the opposition from the window on the second floor. On Afghan, the side that spawns near the irradiated zone will usually win as not only can they control the sniping point on the cliffs, but can also openly launch grenades through the open rear of the cockpit onto the nuke or control the concrete building overlooking the other spawn. The only difficulty is the spawning system which causes this team to spawn frequently on the cliffs, however, Commando Pro or a careful descent can solve this issue.