Here's my .02
I would like a 16' or 18' flat bed with 2x8 treated decking fastened with HOT DIPPED GALVY 3/8th carriage bolts.
axles should be 5200# each and, obviously, have brakes on both axles.
somehow, the trailer tongue, and i guess the whole trailer itself, should sit higher than normal so I dont have to use a 12" drop hitch - and to avoid scraping the crap out of everything.
the fenders should be sturdy enough to support my body weight when jumping up on them to get in my rig and the upper fender surface should have a non-slip coating. It'd be nice if there was a step in front or behind the fender - to make it easier to get up on the fender.
There should be tie downs front, middle and rear and these tie-downs should be inboard of the perimeter rail.
Perimeter rail and vertical supports should have a ton of holes for bungy cords and lightweight straps.
Rear should have a full-width drop gate sturdy enough to support the rig.
Front and rear corners should have jackstands to support the trailer so that I can use the trailer as a garage floor.
IMHO wiring should be run in PLASTIC conduit. I'm sick of ripping out rusted metal conduit and corroded wires.
Here's a thought... (i haven't figured out how to do it yet) I like to pull my rig right up to the front rail and use front and rear tie-downs to pull the rig tight.
However, pulling my rig all the way up to the front rail puts a bit too much weight in the front of the trailer. I would like some way to have an adjustable bar that I could slide back or forward as needed - and drive my front tires into that, as opposed to the front rail.
Storage box on the tongue. HEAVY duty front jack with a heavy duty foot.
Sealed LED lights & a lot of 'em!
Now that's what I call a trailer!