I think the reaction people have had to the art we've been shown, and the updates generally, stem from misaligned expectations on two different axis.
First, there was an expectation that the setting and tone of the game would be more surreal and outlandish, in the style of Planescape. I can understand that desire, PS:T is still my favorite game, but the expectation seems to derive from an assumption that given the chance of course Obsidian would make another Planescape (or Planescape style) game. I don't think that was ever a justified assumption. Black Isle and Obsidian have made a lot of games, and only MoTB comes even close to replicating the fantastic elements of Planescape, and even that was still set in the Realms. You can make the claim that this was due to publisher interference, but the creation of Torment was not due to some sudden moment of publisher passivity. It was a licensed D&D product. Even if you just look only at the Black Isle Infinity Engine games, they made one Planescape: Torment, but they made two Icewind Dales. MCA has said that he would like to revisit a Planescape-like setting, but he's only one voice at Obsidian, and he's not the project lead.
It's clear that the world of Project Eternity is meant to be a much more naturalistic fantasy world. Their approach to world building is to take a few fantastic elements (souls are a source of power, there is this set of fantasy races, gods exist, but are meddlesome and untrustworthy) and to build the world around those elements by basing it on historical analogies and then asking "what if..?". This is a totally valid approach to building a fantasy world, but it is not an approach that gets you something like Planescape. The types of settings give you the opportunity to deal with different thematic elements. In a fantastical setting like Planescape, you can best explore themes that are more metaphysical and existential in nature, questions about the nature of belief and reality. A more naturalistic world, one that has more parallels to the world we inhabit, allows you to better address social and political themes. You can explore issues like discrimination, government, poverty and war in a way that feels relevant to the player. Again, I think both of these are totally valid, and it sucks for people that were really hoping for one and have no interest in the other, but I don't think there's been any misrepresentation on Obsidian's side about their goals for the setting.
From what we've seen so far, I think they are executing well on the ideas they've chosen to explore, but it is still very early in the process, which brings me to the second point.
An important thing to note is that this game has had something like three weeks of very early pre-production, and that's it. The game is not at the point where anyone in the public would even know it existed if it were being developed under the normal publisher model. When a published game releases "early" concept art, that game has probably been in full production for some period of time. The designs have been completely nailed down, and the concept artists have drawn everything in the game a hundred times. Even if they show concept art that is from early in the process, it was cherry-picked from thousands of drawings. It's probably not a good idea to make judgements about how the final game will look, relative to other games, based on comparing this concept art to concept art shown by publishers as promotional material.
Obsidian is in a difficult position. On one hand they shouldn't be showing art to the public that they're not confident in, but on the other hand it's too early for any of the designs to be finalized, and the backers are clamoring to see something. This applies equally to questions about rules and mechanics. They can't release, for example, a walkthrough of character creation, because the character creation system hasn't been designed yet. Possibly Obsidian's real error was not self-funding a longer pre-production period before launching the kickstarter. Doing so would probably have prevented a lot of the blow-back they're getting.