Since there is future tech in the game, I think that gives them plenty of wiggle room for future bosses and raids. So many raid mechanics can easily be masked under "tech". I don't think the Division is going to have Destiny like raids, but the settings isn't the reason. If they wanted to, I am sure creative types could easily make complex raid mechanics using the Division assets.
Agree with this. While not having "aliens" or something does make it harder to come up with enemy types, bosses, etc., there is a lot they can do (think the more reasonable end of the MGS spectrum: Sniper Wolf, The End, helicopters, tanks, etc.).
Even just the area of NYC definitely in the game offers lots possible locations like subways, Penn Station, Times Square, Empire State Building. etc.
Put this together, and you could easily set a raid in the Empire State Building. Breach a perimeter using the subway tunnels. Use the elevator, then the shaft to move up the building. Maybe have to venture outside on lines or window-washing platforms. Eventually get to the top and have to fight helicopters (an attack chopper and transports with dudes that drop out). Could be dope.
I do absolutely agree that not being able to rely on fantasy or whimsy to create stuff DOES put the onus on them to come up with varied and interesting mobs and bosses, but I honestly prefer that to "zombies, lol!" and am looking forward to seeing what they come up with.
EDIT: expanding on this, they may have to "break the mold" with respect to end game activities. Destiny did a good job of following the predefined "raid" format, in that they were very linear, had boss encounters at set places, special mechanics etc. While I think the "linear raid" could work in Division (see my ESB example, above), they could also do new things, like needing to track down a sniper that could be literally anywhere in the play area.