I disagree vehemently.
One of my greatest peeves about 3.X and Pathfinder was the fixation of trapfinding as a class-only ability. Every thief had to be a rogue and every rogue was automatically a thief. It defeated the point of dividing the skill system from classes if in order to be any good at this one particular (and particularly vital, depending on your DM) skill, you HAD to have a level in a specific class to do so. I realize this is one hyper specific example, but it was one that Next was very much going down the road of again, with Thieves' Tools proficiency being something that every rogue and only rogues could get. Then they added backgrounds and feats that could also provide it. An option. Another path.
Multiclassing is not always an appropriate answer, as classes include a lot of baggage and assumptions that the player may not want. A wizard who grew up as a criminal is very different than a Mage X/Rogue 1. I like the idea that your history or training can shape you in smaller, more incremental ways than taking a full level of something.