Compare the lettering on the two versions. The use of 3D-ish black and fake embossing on the original makes the letters pop.

The lack of both on the new version makes the letters look like they've been crammed into a tiny space at the top of a big empty ring.

This might have worked with new lettering with different proportions. But it's literally just a flat copy of the original letter shapes, without any of the original context.

The 3D effect on the original print/blueprint/engineering marker/quadrant feels dynamic. The impression changes as you move your eye over it. It conveys movement and substance. It works with the black to suggest a car tire, but also a sophisticated (black...) crafted object.

The new version looks like a printer reference mark. It's just... there. It doesn't do anything.

The grey is meaningless and neutral. Again, it's just there. It fills a space, and that's all. The transparent version doesn't even do that. There's literally nothing there.

Removing the 3D creates a uniform space inside the ring, which is why the letters now look as if they're squashed up at the top for no reason. There's poor alignment, and no metaphorical or literal highlight.

Overall it suggests that management don't care about engineering or about appearances.

There's no accounting for taste. This isn't the sort of thing you can really quantify, and if you do you'll lock yourself into a way of viewing things that prevents you from being a good designer. Design is mostly trying 100 things and picking the good one because you have taste, which is a thing you get through years of study, practice, and reminding yourself that you're a worthless hack at 4am in the morning.

Anyway as someone who's spent the requisite sleepless nights I've been granted the power of justifying my taste. It's not the same as "why" because the understanding comes from a felt sense, and then I just make up some bullshit to explain it.

In this case the design isn't well composed because the removal of the background has left the logo un-grounded. The outer ring is now dominated by the letters B M W, making the design top heavy. Also worth noting is that the letters themselves are no longer balanced. The M and W are no longer the full cap-height in the center, which further unbalances the design by making it lighter to the right. The "simplicity" reduces legibility. The design is now dependent on the color of the background rather than working anywhere. Though I can't imagine a color upon which this logo would work better than the previous one. There's also an unpleasant visual ringing that occurs at hard edged transitions like the center of the checkerboard which was previously mitigated by the dividing lines.

I made a flat version that keeps the black ring and put them side to side. Check this out and you might immidiately see the issue: https://i.imgur.com/uW4TGX2.png

The white letters without background are perceived to be placed in space – you don't see the ring so you assume it is empty. The bavarian checkers in the middle seem to float in midair with letters crammed in above it. And this combination of floating and cramming makes it look bad.

With a dark ring this works much better, because the floating part is removed and the letters are on the ring instead of in it.

Well, since you ask...keep in mind that these are only my opinions:

1. Lack of depth...yes, depth can be introduced in any 2D/flat design utilizing color and space illusions

2. The curve/arch that the letters follow is not fully concentric to the center circle

3. The letters appear to be transformed vertically to make their height such that it fits between the outer circle and the inner circle...this in-turn throws of the original aspect ratio of each letter of the given font

Minor inconsistencies as such are aggravating for graphic designers who generally tend to be OCD. I hope this helps.

IMO, it's because the black of the original logo takes up space, and keeps the BMW text and the inner circle grounded to a larger context.

Without the black, the text and the circle are just hanging out at the top of the outer circle, unbalanced against a large empty space at the bottom of the outer circle.

EDIT: Another way of putting it is that it looks like the text and inner circle could just bounce around inside the outer circle—they are "loose", and, as I said above, ungrounded.

I cannot shake the feeling that the inner emblem should be moved down just a tiny bit. Visual subjective balance is not the same as geometric balance. It just looks visually skewed in the vertical dimension.

What a poor result.