I know it takes all types of players that play WoW. From day one, it never bothered me if I messed up somehow and got killed and had to run back to my body knowing full well I didn’t really lose anything in the process. I may learn to take a bit of a better approach at what I was trying to kill or pay a bit more better attention to actually what killed me.
But it was hardly a fact of a real challenge or even an accomplishment to just level up a toon, it was just a time sink. Once you even done it more than once you more than likely found a way or path of least resistance and increased speed to accomplish it. Or even started to learn to read up online to the countless guides that pretty much told you everything little detail in how to speed level a toon, just like the countless guides that told you how to farm gold.
The thing is WoW is about the easiest games to figure out on your own and if you cant there is so much info online and from the earliest days have been that way. Its never been difficult to figure out.
When it comes to sense of accomplishment that is an individual thing. If one person wants a particular color of roach or cat more than any other, then when they get it. No matter how easy it may be to get. They may very factually feel accomplishment from it. Anyone else may could care less in getting it. It like the end game, many have various feelings on just what it is in the end game that gives them a feeling of accomplishment.