FII was very much mostly short songs, especially compared to DT12/DT in general. The longer ones are the exception, and it still has a lot more shorter songs (and much shorter) than the songs on DT12. And while they don't often do whole albums like that, they've regularly done shorter songs throughout their career, like Another Day, CIAW, TSCO, TALW, IWBY, Forsaken, Wither etc. And I think IaW, Awake and FII were all just as concisely written overall.
In no way is writing slightly shorter songs, or even a whole album of shorter length songs breaking new ground for DT. Only for DT/prog would they even be considered short songs to begin with. It's a change compared to recent DT, but it's not new ground for them.