You know you could just tone down the Urban Pgren's armor and I think the inability to retreat is a fairly big handicap.
Opinions, I guess.
Personally I think removing a core gameplay mechanic in favour of a near-endless stream of MP is a really, really bad idea. I dislike Industry and NOSB from a design standpoint.
Urban Assault is fine, once balanced. Like you say, their armour can be tweaked.
I wonder if we will ever see them.