IMO the reason small battle rooms failed is that as some people touched upon, is that free basic cutters are allowed in and just became a no loss troll fest on anybody wanting a legitimate battle.
To the people who say dont allow dueling rooms of whatever size as it will decrease OW participation, id tell them there are already people working the system to acheive this anyway. also remember that the game has bled people who want only pvp and this could induce them to return.
Allowing only same nation duels unless competition will only make people join the same nation.
Training rooms and Duel rooms should be a separate topic:
Training rooms should open and be able to start with no opposition so that clans or groups (or individuals) can practice maneuvers and evolutions without enemy, or be able to split your own group up and be able to practice enemy approaches ETC.
Duel rooms should be just that and for the most part be loss/XP/Gold free.
What will be annoying is that you will have to grind in OW just to be able to play in the Duel rooms so in the long run the question of a list of basic even ships being available to fight in may come up. Maybe not the whole lineup like sea trials - but a few select ships
My 2c
Dazed