Just chiming in with some info that may or may not be of importance -
Disneyland is right in the heart of the giant thing that is Southern California. And for many locals, going to Disneyland is as common as going to the mall. There are annual passholders by the jillions (I have heard as many as 600,000 - the park can only hold, what 70,000?) because a Premium annual pass to Disneyland is still only about $300. Then there are lower levels of APs which become increasingly less expensive. This has had a side effect of allowing Disneyland to become an easy REPEAT weekend escape for many locals on a budget. If a local goes to the park just a handful of times they've covered the cost of admission and the rest of the year - is gravy.
And Disneyland (and resort) is a tiny place (when compared with the 46 sq miles of WDW).
Of course, Walt had no idea how popular this park might become or he may have attempted to buy even more orange groves and make the place bigger to accomodate tens of thousands of people a day - but that's as maybe. Disneyland as built was a fairly isolated, small (by today's MEGA-POPULUS standards) location - Anaheim today is much like the rest of LA: dense, asphault covered, cityscape.
But what adds to Disneyland's congestion (on TOP of the HALF MILLION PLUS annual passholders) is the frequent "local discounts" which adds to the people who have been so often that they feel they have the "right" to do certain things and behave certain ways because they think it is "their" park.
And they ruin it for every other guest. ESPECIALLY for out of state guests who expect the original park to be the best (and yes, sentimentally, crowds or no - it very much is).
Don't get me wrong. I love Disneyland. I go there 8 to 10 times a year (we live 35 miles away) - but the crowds are often unbearable. I hate to say that. I LOVE the company. I WORK for the company.
We were there 3 weeks ago and after 4 hours I had had enough. People cutting in line, strollers banging ankles, nowhere to move in crowds (and we know ALL of the In's and Out's and SECRETS of getting around DL) rudeness like you would not see anywhere else - let alone the Happiest Place on Earth. I told my wife "this is not why I come here".
And then there are days like yesterday. A Saturday in late June:
We rode 11 attractions (without really trying hard - 2 Fastpasses all day)
Sat right at the foot of the castle for the fireworks (a 1st for me - in all my years going to the park I've never been so close - and this 50th show is just AMAZING)
Met and talked to lots of wonderful people who were on vacation from around the States
Saw few "undesirables" roaming the park
And had one of the TOP TEN best days I have EVER had at Disneyland
Luck of the draw I suppose.
But Disneyland will always have it's own unique set of obstacles that it must always overcome that WDW will never face. Much of which is due to it's size AND it's own popularity with the local fan base. LA area is about 14 million people - all within an hour's drive (or so) of the 55 ACRE park of Disneyland. The 46 sq MILE WDW resort is next to a city of what? 1 million? 2 million?
This is why Walt & Roy bought all the extra land in Florida for the 2nd time out. They didn't want liquor stores and sleazy motels across the street.
Plus I believe tight spaces have a tendency to bring out the worst in people and the LA area is, on the whole, a great deal more rude than most other places I have lived and travelled.
All visitors to Disneyland should keep these things in mind and plan accordingly.
I'm not making excuses - these are just my own observations - from close to the situation. I think a traveller to Disneyland should go with a mindset of going to see the Original park as Walt dreamed it and to walk in Walt's footsteps....to see the park (especially the facades of Main street & the structure of the Castle) as Walt envisioned.
Maybe as an adult traveller from elsewhere in the country (or world) one should go to "Walt's Park" for the experience of being where Walt was and seeing what he made - but not expect the comfort and luxury provided by the wonderfulness that is WDW. They can't compared - one is the size of Boston and the other is, several city blocks in size. And yet they both hold the same appeal and bring in vast numbers of people from around the globe. One is very well adapted to deal with these crowds - the other constantly struggles to deal with crowds in a limited space.
In that light I want to add, the tenured CM's at Disneyland do a wonderful job of bringing the magic to everyone they encounter everyday they are there.