Yes, McVay runs a West Coast offense, it's a slightly more vertical one if I recall correctly, but it's a West Coast offense. Goff ran a lot of concepts and plays in college that was taken from the West Coast offense and adapted for an Air Raid offense. Concepts like Levels and such. His ability to be shifty in the pocket and deliver a strike makes him perfect for this type of offense.
This is the same type of offense that Atlanta runs with Matt Ryan, which makes sense given that Shanahan came from Washington and ran it there as well. Funny enough, everyone has said that Jared Goff's NFL comparison is, you guessed it, Matt Ryan.
Sean Mannion's issues with his throwing motion, footwork, and how he holds the ball makes it more of a challenge for this offense. He also struggles with accuracy on deep throws, especially if he needs to roll out an extend a play for something to open up down field. This is where Goff's superior pocket presence and general shiftiness in the pocket puts him at an advantage over Mannion who tends to stand still and isn't as slippery or comfortable in the pocket. Sean Mannion could fix this and become more comfortable in the offense, but naturally Goff is a better fit.
Goff didn't look as comfortable in the Rams offense because it wasn't the best for him, but McVay has an offense that is much better for Goff in terms of fit. Mannion was a better fit for the Fisher/Boras offense.
