I wouldn't worry about that. They just included it to emphasize the wild-frontier angle they're going for through a teaser. The actual score will stick to Mass Effect's signature sound.
That is why I have a lot of problem with it. The choice of music and the N7 armor design which clearly show a hint of cowboy scarf.... then they show the "Western Approach"? Cowboy vs Aliens? Right.... "This is the story of the USS Texas. Its mission, to colonize new world, to discover new aliens and to bang that which has never been banged before".....
If there ever is a teaser that made me think of not buying something that I have already decided to buy, it is this MEA's teaser.
Not to mention the leaked scripts - To find hidden vaults of an ancient civilization. That music, that desert, that jet pack and VAULTS!? Vault hunting? Vault hunters?? Borderlands anyone? Borderlands cross Titanfall/Advanced Warfare.
DAI's teaser and trailer made me want to buy the game... MEA's teaser? Pure PTSD after watching it.