I never really understood the explanation of it is easy to predict. From my own experience and talking with others, there are times where you can try predicting it, but most of the time in a match rolling is something you just end up reacting too and take into consideration when you make decisions.
For example, if during a match I continually keep trying to space a jab or ftilt near max range as Falco, if it happens to whiff due to a roll, then the roll most of the time puts a person at the correct range that all I have to do as falco is turn around and jab/grab. There, roll punished pretty simply.
In another case, say a person is downed on the ground. A position where they can only stand-up, get-up attack, or roll. Well, since I know this downed character has only those 4 options, I can pretty easily cover three of them. Stay just outside of the get-up attack range. If they attack, I won't get hit and I can rush in with an attack. If they stand-up, same thing. If they attempt to roll behind me or towards me, I can react to this as well. Its only roll away from me that is harder to cover, but if near a ledge even that is easily covered.
But, I wouldn't say you should stop rolling altogether. Simply recognize that its not perfect and it is something that if abused would normally be stopped by another player time and time again. If anything, its best to learn to recognize where rolling cannot be punished. The downed character situation of roll away I gave is generally a good one. Although, there are lots of other situations to consider that you sort of only learn through experience.