Why would it be better?
Because I've honestly had serious difficulty recognizing from above a ship that I built in 3D. The top-down view just didn't resemble what I'm used to seeing, partly because it makes a ship flat when some vessels are rather tall, vertically. There are identifying details that simpyl aren't visible.
It seems like it would be less recognizable?
Not to me; I get to see the whole ship--which we do see even during fleet battles, since ships bank when they're turning--instead of just the top-down view.
Anyone here want to put together a mockup of the difference?
I thought I had. Posted it up above.

You can see that big tall one at the bottom; you don't get that sense of size from the icon that results. It took me a while to spot it in the ship-selection screen simply because I couldn't see those vertical towers; the icon looks flat.
By the same token, the one above is the exact opposite; it's rather flat, and you don't get a sense of it from the top-down icon; that ship could be any size at all, vertically.
I just don't get the same sense of the ship I made from the icon we get in Fleet Battles. They don't look the same. And that's just two; there are others, but I've built quite a few, so I only used two examples.
Now...um...I have more to say on this subject, but doing so would kinna violate that whole NDA thing. I've mentioned it in the forum where those with access to Chapter One can post; it's in my personal First Impressions thread.