If they keep handicapping WoW you will be able to just mash random keys and do well. Already there are some classes that pretty much have a 3-key rotation (or a single key macro). It's also a bit frustrating when you've done some of the harder content to gear up and the next expansion gives greens that exceed your "epic" gear's specs. Other crazy stuff they've done includes signing up a friend and getting 3x experience when playing in a group, ability to port each other to the other's location, etc. Might as well start at level 55+ -- oh, wait, they already do that too. Having a single level (70? 80?) toon lets you create a death knight on that same server that starts at level (55? 65?) Some of the issue is the grinding -- so many things you have to do, so many hours of menial tasks / quests when starting a new toon, you get really bored really quickly with that.
Actually, once you have a 55 on any realm, you can make a death knight on any realm. Not just the one you got the 55 character on. It can also be the opposing faction.
Term, holidays, term, holidays, till we leave school, and then work, work, work till we die. -- C.S. Lewis