A project like Titanfall isn't going to be able to treat an engine as a blackbox library. They're going to spend a lot of time tailoring that engine to their needs.

Anytime a game developer is asked to publicly comment on using an external party's engine, that developer is probably a producer and wants to make their project look good. They don't want their game to be seen on the same level as games that CAN get away with treating the engine as a blackbox. The exact reasoning they give (or internet apocrypha) are generally not very useful to understanding the changes they do make.