Wow, lots of me

To add to that:
Domination Mode basically will consist of several maps, which will be controllable. Unlike TC they will not always be accessible and unlike TC there will only be a finite number of players allowed to the fight at once - which will be controlled by NPC factions "hiring" players, up to the allowable number ... which more often than not will all be taken up by pre made player teams.
It will also seal off after the two sides are allowed to enter and no reinforcements can get in. You are essentially locked into a tactics like scenario of two equal sides with the winner coming away with a reward (ammo, weapons, crafting facilities, etc). Obviously theres a bit more to it than that, but thats the quick synopsis.
Faction Scenarios, depending on who you ask, can either mean the various PvE solo/team missions which can earn the player faction points, or large scale PvP involving lots of members of NPC factions periodically fighting over control of a key area - both of these will happen, the name can just apply to both.