Well, I like to sneak as an archer, with light armor...
I also like to crush skulls, as a beast, with heavy armor...
I also like to entertain, with magic, naked... (Not sure about that character, but it is fun to play and explore.)
Obviously, you can't do that with one character... and be good at anything you love, just be average at everything. Thus... Multiple characters... multiple areas of development...
Thus my simple batch-file character swapper. Makes games with multiple profiles easy to play.
I never play the same, ever, except the beginning, to get essentials. I like to break quests, which is easy to do in this game, when it runs. (Thanks to the DRM update, it only runs for bursts of 2 minutes to 15 minutes now.)
Surely it doesn't matter whether your an expert in what you do for your level or not? As long as if you can kill your enemies what's the difference.
For example at the moment I am 100 one handed, and I really hate using skills that are 100 because I don't gain anything out of them so I am moving onto two-handed, before maxing one-handed I used Restoration magic a lot but now I use it less often cos it's a pain constantly switching to healing magic and then back to my Wuuthrad.
I don't see the difference, if it was an MMORPG then sure, you want to be as powerful but the lowest level but this is offline.. All that matters is whether you can crack some skulls.
I still don't understand wasting time doing the same starter quests when at least 50% of the people who do that will never do all the quests, because they will get bored of the game and stop playing it but if you focus on one character, all your progress will be on one character, along with your quests, so you don't get confused with what quests you have done.