It makes sense. I noticed the performance was slightly worse on bf4 after the millionth content update recently.
Driveclub has had a lot of updates too and you can notice one or two little glitches if you've got an eye for spotting those things.
I think it's to do with this. Developer makes a game and they get it up and running in its release state. But they struggle to keep that standard when a ton of bells and whistles are added in. That's my theory but I could be wrong.







