When I did the freighter rebalance, all freighters were tested on their ability to dodge fire (since that's pretty much the only testable characteristic they have), and the Kestrel performed exceptionally well, much better than the Dromedary. It also has pretty good stats in numbers and no weaknesses in arcs, that's why it wasn't buffed when most other freighters were.
Shape/size is something that's very hard to judge by looks alone.
The Bactrian (and the Correo, and a few others) were judged by different, higher standards to reflect their more combat oriented role as unlawful freighters, that's why their stats are so good (also the Bactrian performed badly in testing which was part of it).
It certainly wouldn't hurt to give it more cargo space and it wouldn't break anything to make it faster, but believe me when I say it's a lot better than that comparison suggests.
Edit: In the very subjective scoring system we used, going from !!!!! for the worst performer (Aurochs) to ????? for the best performer (Annapurna) the Dromedary scored !! and the Kestrel ??.
It was all very scientific.
also don't look too closely at the Courier it's fine don't worry about it