My expectations are somewhat hopes:
Poison Gym Leader: we haven't had a legitimate one since Koga - Janine was the same gym location (so I really don't count it as another), and then the only other gym was Virbank and Roxie was kind of an afterthought Gym Leader.
I have the same thoughts and I hope we get the Poison gym a little later then usual, so the sixth or seventh gym.
Dark Gym Leader: no brainer - we've never had one, before. It's about time. Plus, with the concept of Sun and Moon, an eclipse (meeting of the sun and moon) would be a perfect pretense for the standard 7-8th gym interaction where the region Legendary is encountered -> Dark type & eclipse.
Yep, we certainly need a Dark type gym. Though I actually hope its early, because due to having three Dark type Elite Four members we've faced the Dark type at high levels quite a bit before and I want to see a Dark type specialist early for a change. Gym 2-4 would be best in my opinion.
Fairy Elite Four or Champion: we just got our first Fairy Gym Leader due to the introduction of the type, I'd rather not have them just throw another Gym out there in the following generation, but would like to remind people it exists (not that they needed it)
A Fairy Elite Four would be cool, but I dislike the idea of champions being type specialists in general.
Rock Elite Four: every time this type appears, they always get thrown in first, which doesn't do the type much justice
I agree and I'm hoping for a later Rock type gym leader or Elite Four member.
Bug Elite Four or Champion: I know Bug was just in Kalos, but it's there with Rock type in being early game fodder, though Aaron was a nice change, so I'd be a bit more interested in a Bug-using Champion (moreso than Alder)
Whilst the region does really suit having a Bug type specialist and I can very much see it being a late game specialist this time, I'm personally actually hoping we can skip on Bug types this gen. We've had Bug Type specialists in every game for the last three generations (Aaron, Bugsy, Burgh twice, Viola) and I'd like to see it take a break.
NO Electric Gym Leader or Elite Four: we've had one in almost every generation - Lt. Surge, Wattson, Volkner, Elesa, Clemont... it's about time that we DON'T have a region with it (Johto sort of counts, but you still face Lt. Surge when your character goes through Kanto)
I really hope we don't have an Electric Gym Leader this time around and I don't think Hawaii suits having an Electric Gym Leader, I'd still like to see one in the Elite Four as thats never been done before.
NO Water Gym Leader or Elite Four: this one is kind of hard, seeing as Hawai'i is an island and it's...surrounded by water, but it's with Electric type on record as appearing quite often - Misty, Wallace, Juan, Crasher Wake, Cress, Marlon, Siebold...
I would like to skip this too, but we have concept art of what appears to be a Water Type Gym so it seems pretty likely it will happen, though its not a given.
So...my picks (in no particular order)
Gym Leaders: Fire, Grass, Poison, Ground, Flying, Ghost, Dark, Steel
This is pretty simillar to what I want, although I'd rather see a Psychic Gym Leader then in there somewhere and I want Grass to be part of the Elite Four.
Elite Four: Normal, Bug, Rock, Fairy
Rock and Fairy I agree with, but I'd rather see Grass and Electric in the place of Normal and Bug.