The fact that you are overlooking is that WoW is a multiplayer game, and if the population of a realm is spread too evenly across 80 levels, it becomes very difficult to find people to play with.

The point of the changes are to speed all the alts and new players' progression into "current" content so that everybody can play together.

Have you played on a full server? Blizz can't handle that kind of load very well. Even with a full server, if you spread the entire population across all 80 levels, everything gets kinda deserted. I am an alt-aholic myself, and I play on a low-medium population realm, and I can almost never find a pickup group for dungeons in the 25-58 level range.

And, to repeat what others have said, speeding up travel is hardly making it "easier".

Forcing people to run on foot everywhere was always kind of a crappy money grab on Blizz's part. The longer it takes you to get places, the more $15 installments you must pay. It makes absolutely no sense that there should be any level requirement on any mounts anyway. Last time I checked, in real life, and in most fantasy/science fiction, there has never been a link between a person's battle prowess and that person's ability to ride a horse.