I doubt we will see any new maps out of HTC any time soon (I'm talking years, not weeks). Hitech has said that if he hired someone to make maps the first thing he'd do is give them a bunch of other projects to do first.
Custom arenas, AvA, EW and MW are NEVER going to have the popularity that LW has. Too many feel the need to run with the pack, or fly the "monsters" to really make a shot at the other arenas. Both EW and MW have all the same aspects... 3 countries, strat, captures, win the war... and only lack the late war monster equipment, and they NEVER have the population that LW has. AvA and custom arenas have the late war monsters, and even have new maps but again do not draw the people in, and most likely NEVER will. Sure they have small resurgences, but will NEVER have a sustained population.
So time has proven that the majority of the people want to play in LW no matter the changes to the other arenas, or additions of new ones (custom and WWI). So what is the problem with the maps in the LW main? Nothing really, the problem is with the play. Game play has degenerated down to up a horde, roll a base, repeat. A new map isn't going to change that. I got to fly on "Grinder" this week. I think it was only the second time for me, so the map was pretty new

Any new map is going to get the same treatment the olds ones get, so I can see why nobody including HTC would bother making a new map. If I was the one who built the Grinder map I'd be ticked off that I've only got to fly on it twice since it was added.
No, new areas and new maps aren't what is needed. New game play is. I still see people posting its a waste of time to hit the strats, basically because they just don't know. All they know is horde a base, capture it, and move on to the next one. People are bored, but it has nothing to do with the maps.