My list is quite long, I'd like to see:
- Anvil with same cv shaft for both sides
- lockers - always, automatic, or manual
- R&P gear selection
- full floating rear axle
- dual t-case
- yoke output t-case
- rid of the center bearing driveshaft
- rid of the rubber isolator joint on rear pinion
- swing up rear door window with split swing open rear tailgate ie. late model Astro van
- swing away tire carrier
- auto trans/engine curve adjustment
- front, rear bumpers
- nerf bars
- belly pan skids
- interior cage
- removable seat covers (leather preferred)
- supercharger
- diesel engine, n/a & turbo/intercooled optioned
- hi-flow cat-back exhaust
- non-pressurized front diff
- turn off/on DRL's
- turn off/on air bags (4wd low only)
- larger gas tank with less ground clearance
- better stereo speaker locations, with more speakers
- manual windows and door locks
- rid of the double hit lock system
- add power window/lock control to passenger front door
- and most of all rear theater seating, ie Xterra, providing rear seat passengers better front view (my kids need this)
So just a few points, most to all these can be done on my own, but I'd prefer to have it already designed in.