I would too. They made changes for sure, beyond the obvious, engine and Trans, the rear axle is different. The US ranger uses a common axle that both the Chevy Colorado ZR2 and Jeep Rubicon use, lockable 220mm, sourced from the US distributor Dana. The interior looks to be effectively the same along with the body. Frame may be different as well, though they are both fully boxed.
The global ranger can carry significantly more than the US ranger, close to 700 lbs. Based on what I've read between the Hilux and Tacoma, folks generally think it has to do with Frame integrity. I believe the Hilux is fully boxed while the Tacoma (last gen at least) was C channel, which is a can of worms I don't want to open. I know the Ranger is fully boxed FWIW. I'm sure frame strength certainly has something to do with it, but also suspension stiffness / acceptable NVH (lets be honest, what's ok in AUS and Africa isn't going to fly here) and gov stipulations all come into play.