It will be difficult to make a total redesign to the FJ Cruiser since it's suppossed to be reminiscent of the FJ of old. Very little cosmetic features were changed on the current version, maybe some options where standardized or removed, the only major change I think was that the rear diff changed.
It would be interesting if they revived another blast from the past after 10 years of FJ cruiser. Unless the looks of it are still viable to keep going another 10. Interesting would be a 2 door, FJ convertible. But I seem to have seen somewhere that Jeep actually has some kind of design patent on that classic Jeep design now. If that is true, then a 2 door or 4 door FJ converible with more retro styling would not happen.
If they go on with the same design, if it continues to be deemed viable, knowing that it is retro, so if that is what you like then it doesn't matter if the styling doesn't change....
Then maybe they would just continue with mechanical changes like more engine options. With the FJ in Europe and Australia, maybe, just maybe a a factory deisel option might make it's way into an FJ cruiser. Or a hybrid, or a smaller gas engine with turbo or supercharger and more gear options like a 7,8speed, different gear ratios in the diffs, a lower low range. Maybe keep it fresh by offering a upgraded offriad package like ARB bumper and winch from the dealer that you can then finance with the purchase.
I like the FJ. It's a cool truck. It's retro styling, so I don't really mind if it doesn't have a total extreme makeover.