One thing that has always bugged me, though, is the fact that humanoid characters just don't look good from the top. Try it. Perch on a balcony or second-floor railing at a mall or something, and look down at people. (Try not to be too creepy; a little creep is fine, but let's not go crazy here.) How uninteresting are folks when seen from straight above? Very, I say.
Some types of creatures work well with top down; I worked (briefly) on a top-down shooter/RPG featuring bugs. Bugs as the main character, bugs as the NPCs, bugs as the enemies. I still like the game idea I came up with there, and would like to work on it again someday, but for the most part the stories I want to tell involve people. People, I think, stand at the heart of RPGs. While you can introduce people-ish attributes to the bugs, but it's kinda hard to identify with something creepy-crawly.
I have yet another little project in the wings that I take out and tinker with every so often, called Archipelago, a boat-centric exploration RPG taking place in a randomly-generated chain of islands. I've been tinkering with it again, having grown tired of wrestling with 3D on my sub-power laptop, and I've revisited, again, the process of creating the character graphics. I've been naively rendering the character sprites from full top-down for mathematical accuracy, but tonight I experimented with tilting the camera just a tiny bit to get a slight bit more of a frontal view of the character. Here are a couple tests (pay no attention to his gnarly Cheeto fingers and the weird cat on his head; he's still a work in progress):
I'm sort of leaning toward the center example, rendered at 15 degrees off-axis, IIRC. It gives enough frontal to establish some of the details of the character, but without appearing to wonky and off-kilter when the sprite is rotated. The top pair is straight top-down, and demonstrates all that I find awkward about top-down: you can hardly tell what the character is really supposed to be. The bottom set, rendered at 25 degrees, is just too much, making rotated sprites feel like they are in danger of falling over or something. I might play with the actual tilt just a tad, but I think I might run with the 15 degree tilt for awhile to see how I like it.