Funny how DS9 did a better job developing its guest characters than VOY did with its primaries.
DS9's guest characters were powerful religious icons, powerful warlords, former spies, etc. They were inherently more interesting characters to begin with.
VOY had a native American into native religions, pirates, a self-loathing half Klingon, a character facing mortality far sooner than her contemporaries, a drifter, etc. There was a lot of potential there for great character development. Its a virtual Canterbury Tales!
I think the only ones with bland backgrounds were Kim, Tuvok, and Janeway. The sad fact is the writers just weren't creative enough to make interesting stories with the characters they had and found technobabble more interesting than character growth and meaningful commentary.