They offered the Black Trail with corrugate siding through 2014 I think.
Corrugated aluminum is not lower maintenance. No way would I ever consider getting another trailer with it. Our Jayco had it. My ORV doesn't (my Weekend Warrior was also fiberglass).
The aluminum siding is prone to dents, holes, and tears when dragging it off-road. Caulking doesn't last neat as long because there's so much more body movement. The body isn't near as stiff. The Jayco had to have its curbside wall rebuilt because the framing failed. Composite structures are just stronger and more durable.
The stuff I've put my ORV through is pretty impressive. I don't think ORV has cut any corners design-wise recently, but they've likely has more issues like everybody as they try to crank out as many as possible with a reduced labor-force.
2000 Ford E450 V10 VAN! 450,000+ miles
2014 ORV really big trailer
2015 Ford Focus ST