Once again, my take on how these elements should be handled in the remake:
The World Map
Have you all played / seen Episode Duscae? That. I want a world map like that.
The Flashback Sequence
I have to be honest the flashback sequence I find unbearable in the game. I know it's a huge pinnacle of the story, but it's not a really enjoyable sequence IMO. It's something I would prefer to see done as a cutscene. If they must keep it as a gameplay segment, I would like to see it shortened down.
Ch-ch-ch-chocobos!
Capturing wild chocobos and taming them seems like it will be a part of FF15 so it's definitely doable in HD. But how will they handle the scene with the Midgar Zolom, which apart from the end-game material is the only real reason you need a chocobo? I think there's a great opportunity to turn this into a really tense battle / chase sequence. I wouldn't mind them making big changes to this part to make it more climactic.
Mythril Mines
I keep referencing FF15 and I'm sorry, but I would love it if the Mythril Mines were laid out like the cave in Episode Duscae. You know, where it looks like an actual cave. Dark, kind of creepy, cramped spaces. That would be awesome.
Fort Condor Battles
They need to keep this. It was like one of my favorite mini-games. I think with the possible HD scale it could be made even better, reaching full RTS heights. I envision this being a sort of resource management thing that you can get updates on your PHS regarding to keep you up-to-date. Which reminds me...
PHS
Forget party changing, this will be everything. Texts on updates from your contacts, your menu, your bankroll, managing your sidequests, perhaps even bonus objectives. The PHS better be awesome.
Junon
Keep in the dolphin. But don't just keep it. Lampshade how utterly ridiculous it is. I mean they already kind of did anyways, but more... more. I want like... well that image Mr. Ite shared levels of ridiculous. And the Rufus Welcoming sequence too, leave it exactly as is. Side note: if the TV commentors for the marching scene are named Jimma and Bobba I will laugh my ass off.
Cargo Ship Sequence
READ MY CAPS LOCK. KEEP NANAKI ON TWO FEET. KEEP NANAKI ON TWO FEET. KEEP NANAKI ON TWO FEET. THAT IS ALL.
Costa Del Sol
Expand this beach area, and keep in the villa for the yucks. I would love to see this coastal resort fully realized.