I notice these characters all have their supers and wearing legendary & some exotics..that's clearly later activities. With the idea that we'll be living "without light" I'm very hopeful this will be very central to the story, and strategy, early on. I'm assuming there's a time where we're very basic scrubs (a la beginning of D1). You'll be jumping for joy when you get your first green/blue. This is probably why engrams weren't shown. This was a very carefully crafted/controlled demo/intro to the very basics of the game.
Clearly we've only seen a very small glimpse of what's to come. I understand people who gave up on D1 early that are still feeling burned/untrusting of Bungie -- they do kinda deserve it. However, speaking as a fan of B and D1, I'm still really excited. Think back to how different vanilla D1 is to what we have today. I'm fairly certain this game will evolve over time as well. We didn't get the third subclass until year 2, right? Remember when cutscenes couldn't be skipped?
There is a balance to be struck when doing a sequel. You can't just rehash OR throw-away everything. Some things need to be consistent. Halo 2 seemed amazing to me (both graphically and gameplay wise -- I admit, I loved dual wielding)...but the changes were radical enough that they needed to be toned down in Halo 3, but we got 4 player co-op! There is no correct/complete set of what should stay, what should go -- someone is going to not be happy.
There are some personal pet gripes/wish list that I hope get addressed in some way:
Menu interruption...please STOP dropping me out of my menus during in-game transitions. Its the 21st century, the menu should be a threaded OS task and not interruptable by gameplay (even if it kills me)
Enemy variety in world. They kinda started this with the variation on strikes, but I'd really like to see different enemies in areas and have them move and change more in the patrol areas...knowing where the yellow-bar captain is always going to be is so last gen. Make it fresh, make it dynamic. I especially love when two factions start fighting each other.
Weapon building/crafting/upgrading. They do such an awesome job of crafting/modeling weapons and in the end, we only end up using a very small portion (I recall in early days of D1 there was some awesome looking hunter gear that was green). I think a better system would be able to upgrade anything up to legendary status. In the end it may cost a lot, but there is sentimental and aesthetic preferences that players develop. This would also mean a ton of content doesn't get jettisoned. I think the infuse is a crutch to keep their end-game items up to date, but honestly, I'd like for any item be able to be carried forward, even if its very costly.
Greater customization. Weapon & armor ornaments are close, but I think they can do better. I'd like weapon shaders/skins as well for legendary, not just exotic weapons. User-editable shaders, even if its a limited palette would be amazing.
Vehicles. The sparrow is purely for getting around on the map. While useful, I feel there is a missed opportunity. Again, looking back to Halo, there was a variety of vehicles. I think a three man hover tank with side turrets would be awesome, or a two man "helicopter/hovering" attack vehicle...if these new maps are so big, then vehicles shouldn't break the game.
I think this game is going to be amazing. I don't think we've seen anything really surprising, and that's Bungie by design. The best is yet to come. I expect E3 and post E3 to really get the hype ramped up.