I definitely think an arena that is all AI, has every "type" of mission for beginners, from fighter sweeps, to bombers bombing, to GV's doing there GV thing....
I would say it should not be mandatory but optional, give them incentive though, every "mission" completed they earn perks that can be used in the MA,(the better in the mission you do the more perks earned) this arena shouldn't just be for noobs though, any one can go and earn some perks and practice, with out having to do it in the MA, to get ridiculed when you drop bombs on your own field.

this would go a long way to get the noobs up to par for some MA fun.
I can see the "fighter" mission, you pick the nme plane, situation, number of nme's, ALT, load out, then you go do the mission, x amount of perks for every nme plane shot down.
a new "war" arena that is not necessarily replaying the exact way the war went down, but instead of knights,rooks,bish, its the real countries.
when you first sign into the arena you sign up for what you want to play as, IE fighter, bomber....and what country you want to fly for.
this could have squad made missions and/or single player mission, along with AI missions that you could join.
with this arena, the two main LW arena's could be dissolved into one, the player base would be spread out through out the MA's,WAR arena, and training arena's, so the cesspool of the one main arena would be nullified.
change the dynamics of the MA's to a local eny(depending on the number of friendlies/nmes in a given area will depend on perks earned), perk EVERY plane, a spot on every map that has a fighter, and GV, area that cannot be taken. more ground targets to destroy, bridges, trains, and what not.