It has been a long while since I was on a KL shorthaul flight that wasn't completely or very close to completely full in Y so I feel like that isn't going to be a big problem.

Also, while these A321s are the first to be delivered, some smaller A320s are also on order.

That said, as a tall person, I would of course have preferred a couple rows less. But I also always sit in economy comfort or the exit row(s) anyway so it barely matters to me.