I've never understood in all my research of AP, what it is exactly that people see when AP'ing.
I am not sure what sort of research you have done but I would say that what people "see" varies widely from person to person.
Does it seem like a normal waking state? Can you see the same colors/objects, etc, as if you are awake? Or is it more of a dark/shadowy type of thing - outlines/shadows etc.
For me it doesn't. I know I am not in a "normal" waking state when I go OBE. Sometimes you can see the same colors/objects, etc, as if you are awake and apparently many do most of the time... but my early OBE's were very unusual in these aspects and I only started having some of these more common elements in my journeys when I consciously used "intent" to explore the types of experiences that I was reading from other projectors.
Is it like a conscious dream (I know this refers to Lucid Dreaming, but I know that AP is different)? I mean do you see things like you would in a dream? Humans, textures, colors, landscapes, etc.
Sometimes. If I am having frequent OBEs they begin to take on dream-like characteristics. If I have only one or two OBEs per month the first projection is strong and more Astrally or Causally-ish in nature. If I project multiple times in a row the second will be similar but shorter. The 3rd and 4th projections start to get darker and weaker. The 5th or 6th will be very dreamlike and usually degrades into a long and very engaging Lucid Dream and then I just wake up normally rather than consciously return to the body.