Reminder, "depth", nuance, and complexity or writing with extensive layers, and being well-written are not inherently the same thing.
That isn't mutually exclusive.
You could have the most shallow ************ ever to grace pen to paper and still be extremely well-written depending on how they're used or a character who's extremely nuanced with layers of depth, and be pretty mediocre all things considered.
What makes a character good has a lot more, or sometimes a lot less to it, but it's also completely subjective and is something that can't be evaluated in hard fact or "right" and "wrong".
unless you're me
also put Vampire Hunter D and DCAU Batman in whatever tier they're cooking in atm