Jiko is wonderful! It's usually our only ADR and "must-do" restaurant in Orlando.
We've only had the filet and mac & cheese as our entrees. We've been between 15 and 20 times, and we just can't bring ourselves to order anything else. One of those, "if it ain't broke, don't fix it" things
For appetizers, we've had most of the flatbreads (the one with kalamata olives, goat cheese and micro greens is our favorite). They'll also do a custom appetizer sampler for your group, no matter how small or large your group is, so you can try several things. Keep in mind, we're not on the
DDP. Don't know if they do this for DDP folks.
Desserts, in our experience, are huge, especially the pistachio creme brulee. I'm not generally a sharer when it comes to meals out -- unless we're only talking about a bite -- but the creme brulee is totally sharable.
The wine list ... ahh

The best in WDW, IMO. We almost always try something new and listen to our servers about what's new and fantabulous. We've never had a bad pairing at Jiko, and we always order a bottle of red and white to compliment our meal. I'd never thought a white would pair well with a steak, but leave it to a place like Jiko to change my mind on that one. A buttery chardonnay actually tastes phenomenal with the rich filet and brings out the butter flavors in the mac & cheese.
Like others have said, go early and check out the hotel. The gift shop is pretty resort-specific and offers a lot I can't find elsewhere in the parks or at DTD.