Hello, I am K-vald, animator on Stellaris, and it's nice to see a thread about what I'm doing here as there's mostly feedback about other matters than graphics/animation here

(which is also why I feel that this is a perfect opportunity for me to comment on it!)
I understand your concern about the ships going "downwards" in space, which in all fairness, as you point out, might not come off as too realistic. However, realism vs. gameplay is a very old topic that I think all of us are too familiar with around here..
The reason we chose to go with the "gameplay" approach to this is simply that it will get the destroyed ships out of the way and it shows which ships are destroyed. We deemed it to be best to not have exploding ships and next-to-stationary ships in the middle of combat, which would look horrible when other ships and projectiles would clip though them.
It can also be mentioned that what you see in the video is only one of many different kind of destroyed animations!
I appreciate everyones feedback on the matter, in whatever form (even if the more constructive the better

).