POLE7645: Someone looked at the files for Titanfall and the reason the game is this big is...
Uncompressed audio files for 20 languages. Seriously, that's the only reason. They stated that this did it like this because they wanted to save CPU power (that would be used for audio decompression). Logic states that a CPU that can't handle doing some audio decompression probably won't be able to run this game.
And (to quote TV tropes where they mentioned this game under "Idiot programming") with separate installers for languages and a bit of compression, the game could fit on a quarter of it's current weight.
But it's true that games needs more and more disk space. Just look at the recent Kickstarter-backed games.
- Divinity: Divine Origins: Around 10 GB (not too bad. A bit less than most games nowadays).
- Tesla Effect: A Tex Murphy Adventure: 15 BG (understandable since the FMVs are now in HD)
- Wasteland 2: 20 GB according to the system requirements (apparently because the art assets are in HD. It surprised me because this game won't contain a lot of voice acting).
These are those I can think on the top of my head. Then again, Dragon Age: Origins (without any DLC or the expansion) required 20 GB and that was a 2009 game.
Shogun 2 needs something like 30 GB.
Then again, that's supposed to have individual unit animations and designs, so I guess that's understandable.