Why would you have grouped in D2/D3 but not D4? D4, by far, has the most advantages given to groups out of any game in the series (Not sure on immortal, to be fair, never played that trash)
Serious question. I’m mostly a solo player, and most of the time my characters are purely SSF. But there seems to be way more reasons to group in D4 than there ever was in 2 or 3