I actually think that the Trail/Off-Road versions offer some significant differences over the SR5 as it is, the part-time 4WD system being the primary one. Toyota never should have added added the TRD name to the Trail, it's be like Ford adding Raptor grilles to an otherwise-stock truck and selling it as an entry-level Raptor. Pretty sure Ford knows enough to consider doing so an embarrassment.
The 'TRD OffRoad' is equally poser-ish, as there isn't a single TRD part on the truck (unless you consider embroidery and decals as TRD parts).
Dilution of the heritage, all in the name of marketing.