I would not be angry at all if KLM simply stopped serving those god-awful sandwiches in Y class. I mean, for people that are strict vegetarians, Muslim, Jewish, devout Catholics on some Wednesdays and Fridays during Lent and all Holy Days of Obligation, hyper glycemic, hypo glycemic, high-blood pressure, low-blood pressure, toothless or recently received oral surgery, allergic to something, glandularly obese, etc etc etc.. those silly little sandwiches are not ideal. Now, imagine that 1/2 of a plane is part of this. On a short flight AMS-LHR, I don't need a sandwich. Perhaps AMS-LIS, SVO, HEL, ATH or WAW are better examples when food is proper and a necessity in many cases. It just makes sense to cater a plane with a variety of these 1/2 sandwiches, small baggies filled with fresh, raw, cut vegetables (like carrots, celery, green peppers, and radishes), or pieces of whole, fresh fruit (or even little cups of cut fruit like pineapple, peaches, and berries). People can select one for the short flights to CPH, LHR, and that's it. For the longer flights, pax could choose 2 things. At least, I would be happier with an apple than some nasty, soggy Prosciutto with Cabbage and Mayo sandwich that they claim is an Italian delicacy. I live in Italy. I promise you this combination is neither Italian nor a delicacy.
The other option is to go the way of Iberia, bmi, and SAS and start charging for everything, but increase the number of selections and improve the quality. I'm not against paying for food in Y if it is good quality and healthy.

For the long-hauls, I have never travelled in KLM in Y class, so I really can't comment on much there.