If you think the leveling process in a game like D3 is engaging content, that's cool I guess. But it's objectively such a tiny fraction of the actual experience that losing it just isn't going to have any real impact - especially since it's your choice. It matters not one iota in the big picture, even in highly competitive settings.
It's kind of like leveling in WoW. It's just something you have to do for a bit at some point until the ACTUAL game begins. Skipping that is not just something that has very little impact on anything, it's something people actively WANT because it's such a tedious prerequisite.