I really hope you are right and am relieved someone hears what I am saying. That increases the odds someone at Imagineering also sees the potential clash of themes.
I wasn't amazed by the original FLE artwork because of the enhanced M&G's at all. It was the cutting edge immersion of the land. The entire idea of a forest beyond the castle walls that contained mythical lands with immersive lands within them. Guests were taken further and further into the story. Like a "real life" version of a multiplane camera shot is the best analogy I can think of.
So I just hope (as I have said many times) that they seriously consider properly theming the ride. Big Thunder Mountain makes sense running out of control in the wild west. A smaller version in the middle of a fantasyland forest (that has been so well designed) seems a less likely place for such a theme.
I don't hate coasters and I like this ride. The placement just seems wrong to me. Just an opinion.
I see your line of thinking, and to form an opinion for myself, I took a look at the concept art. I studied the 'birds eye' mine train art in of itself, and then the newly revised concept art, and then the original concept art for reference.
Here are some observations I made after comparing artwork and blueprints:
a.) The expansion is too building-oriented. You can obviously see the m&g showbuilding, though hid by two-dimensional facade of a couple of castles and a cottage, as well as some rock. Because we are not able to see the north-facing side of the complex, I can't comment on that. They did, however, put a large amount of vegetation into the original expansion, which helps hide it a little.
b.) Lack of unity. Though the later design suffers a bit from this, there seems to be no attempt at a cohesive theme or flow. Despite being based off of Disney animated movies (from totally separate eras, I may add), there's not much that the new additions have in common. Where's the flow? How would you thematically link a decidedly tropical tide pool and castle (and grotto) with a French village? Why would you find such a thing in a "Fantasyland Forest"? Of course, this makes less sense with the "New Fantasyland".
c. Poor sightlines. According to the original art, if you're travelling counter-clockwise around the Magic Kingdom from Tomorrowland, how on earth would you be able to see the Little Mermaid attraction or the Beauty and the Beast Castle? Even Pixie Hollow and the Dumbo is off of the beaten path. What we're seeing here is a "pocket" kind of design for this expansion, sort of like Toontown at Disneyland. The main attraction(s) are off of the beaten path. With the exception of the the MK mountains, all of the attractions of the Magic Kingdom are located on a major thoroughfare. The Mountains, however, have wienies to drag you in. Sure, the LM and BatB facades will be prominent, but would you be able to see them across the land? Even if you're coming from Fantasyland West, the Castle Walls will block your vision of anything until you are past them. If the Coaster will indeed be the showcasing attraction of the expansion, it is misplaced- it should be located
behind the other additions in the area, to serve as a wienie to draw people in. Unless they re-locate the exit to traffic guests to the north-facing side of the attraction, would the average guest even see the new area? Heck, according to the leaked blueprints, you wouldn't even have direct pedestrian access from the Tomorrowland area to the Dumbos, or even the Little Mermaid.
If I think of more observations later, I'll add them here.
I have, however, arrived at the conclusion that though the Seven Dwarves coaster is misplaced, the landscaping treatment it will get, along with the open spaces, cottage, green rolling hills/mountains, fits in better than the castle complex, though the New Fantasyland has some fundamental problems both related and unrelated to the Seven Dwarves mine coaster. The Subs ride must have fit better than this.
) I feel as if you needed something to complain about, but I'd say be patient for once and wait. 
