Of course you will be able to sneak around like Bond! I have played just about every Bond game and there are always stealth elements in a few of the missions in the games.
I am guessing you will have to use stealth in every mission at one point or another. With 007 games you always get the choice to go in stealthily, go in guns blazing or to find a different route such as an air vent to go around the enemies.
I sure hope there are secret rooms that you get extra stuff in such as ammo, Armour or unlockables! Since 007 Legends has many classic Bond movies in it with gadgets etc.. I would be very surprised if they didn't include that much stealth in it.
The only reason why the trailers have so much action is to make the game look good and attractive the same as GE reloaded done. But I think there will definitely be some stealth in the missions for example in the OHMSS mission you could sneak into Blofeld's base or go in guns blazing?
Thanks for this discussion