I haven't seen the trailer or played the game myself, but what if what you saw was a small fraction of the experience that is attainable? Wouldn't that be amazing?
The trailer still has to have enough to get people interested, and if it's well made with generous amounts of content it should still keep you amazed and interested.
Again, I don't actually know, but it is on my radar and I have heard good things about this game, so I feel inclined towards the positive outlook in this circumstance.
This was my barrier of entry. As someone who put around a combined 1k hours in the Souls games, it wasn't until I treated the game differently than Souls did I finally start to make progress. Same thing happened with the aggressive, faster pace of Bloodborne.