New Jagged Universe/Arenas
Arenas in New Jagged Universe (possibly not released at launch, since there's still the main SC), will be a location where players can still choose to fight others in mostly structured battles. For example, players can choose to have straight 1v1 duels, team duels, or even some more interesting battle types (IE: "Boss" vs. "Grunts" style fights, maybe?).
Arenas will probably not give quite as much base rewards as doing missions (less PP and Credits. Maybe even need to pay to enter.). However, doing well in arenas can unlock additional rewards, such as unlocking different series for purchase or even earning mecha you might not earn until later (or at all otherwise?).
There should be some regular tournanments as well. Top 3 can win special mecha or other prizes.
In SC terms, the arenas would basically act much like the current SimChambers.
Unlike the regular arenas, VR arenas allow players to make the fight regulations anything they want, but at a loss of almost all awards. VR arenas are mostly for trying out things, such as potential builds.