Combine with that he and zombies can now break in through the doors unlike the older version, and the scarcity of the ammunition and introduction of knife durability, trying to lose him become a bit difficult. And it was already difficult evading the zombies due to the tight corridors. It was more like how he was relentlessly pursuing you while you have to get some key items and do some puzzles (in my view, especially when moving the shelves in the library) until some cutscene events or when you have the rocket launcher. I don't think it is the invincibility of the Tyrant (Mr X) that many are annoyed about.
