As I've pointed out from as far back as 3 weeks ago when I had my 4-hour hands-on, the screen sort of makes sense when you look at it: it's a circle. Noctis' skills cover the top part of the circle, Gladio the bottom part, Prompto the left, Ignis the right. I don't think it's going to 'fill in' because the menu is actually a nice thematic design -- the idea is that the four are a part of a greater whole, and so when you look at all four skill trees side by side they form a perfect circle, whereas alone each is only part.
I do think the ring and the phantom swords will unlock some new stuff, but I'm strongly of the belief this skill tree is 'it' for actual skills you spend AP on. There's skill stuff in other areas for each character's special non-battle skills anyway, plus weapon variety, etc. It's more an action game, so there's less skills they can really implement anyway.
This sounds right to me.
Of course it seems different weapon types come with their own active skills (jump for spears, tempest for great sword), phantom weapons have their own gimmicks, we'll have ring magic, upgradable elemental magic, and who knows what accessories might end up giving us. I've been pleased with how much variety in skill and play style the new footage has suggested. Anyway, Final fantasy has never had a huge WRPG style skill tree.
Sphere grid and crystarium are almost completely status ups.
XII might be the closest, but not too many interesting active skills on that, either.
Also, you'd mentioned the camera wasn't AS bad when playing as it seems when watching. Did you find it an active deterrent to fighting in close quarters?
In Duscae, part of the strategy for fighting goblins is to keep them in front of you/don't get surrounded. When they do start coming from all quarters, it's disorienting, but that seems appropriate for being attacked by a small tricky enemy in a dark cave. Then I'd just warp to a more favorable position anyway.