^Yes I agree, I've attended Disneyland when it was a MAX capacity, and it can be a bit daunting. The hard working Disney cast members attempt to use their glow sticks to guide the massive crowds to go in a certain direction. (even if someone wants to do the complete opposite) To help keep the public moving in a certain 'safe' direction.
Unfortunately do to its original design, there are limitations placed on the Disneyland Park regardless of how money they invest in improvements. With the latest Disney parks, they have incorporated these capacity issues into the design of the park. But with the iconic Disneyland they have to make do with the design elements from 60 years ago. (Walt never could have imagined that 15+ million people would be visiting Disneyland each year)
Regardless, even on those high capacity days, the issues mainly come at night with the combination of the fireworks and Fantasmic crowds, and Disney has a procedure in place that works well enough. (Even if it upsets some guests) Like any other theme park, Disney will do what it can to keep its patrons happy within the design limitations of the park.