I think Bungie mistook "challenging" for "long and boring" - it's just not fun pew pew pew pew pew pew pewing the same servitor for a half hour until he dies, to just move on to the next one, then the next one, then running around in a circle and doing it again. The Kaliks and Skrolas fight back to back is just an incredibly long and boring time suck. I am quite disappointed in it. I am not even joking, and not even exaggerating: I literally fell asleep last night during both battles. My teammates had to call out to me and ask why I was just standing there, and I was like "OH man sorry I just dozed off" then resumed shooting the same enemies over and over again. And despite falling asleep 2-3 times MID BATTLE, we still won. Not a good look, and not a fun fight. I miss raids.