Yes, it was. Apologies in advance for the wall of text below this sentence.
While I can see where the fans might draw parallels between Loki and Scar, they are still too far apart for the characters to be very much alike. Really, what does draw the connection between them is the Cain and Abel trope, and that has been repeated more times than I can count across the pages of time (figuratively, of course).
I can also see where you're coming from between Loki and Kovu, as each takes from the trope of the changeling, or the foundling. Although, I think Loki is more to the Greek Oedipus of the foundling tropes, and Kovu is more to the biblical Moses (the fact that Loki is shown to be missing his adopted mother in the second Thor film reflects this). The major difference between Loki and Kovu, though, is that Loki does not have a morality chain (Kiara would be this to Kovu).
Perhaps if Sigyn was introduced in the films (which I heavily doubt at this point), she might assume this role, but that remains to be seen. Then again, I don't think that role should be delegated to her for three reasons. Reason #1: Sigyn is the goddess of fidelity, and I would think, as according to the norms of her planet, she would fall into step with what her husband wants. A Harley Quinn to Loki's Joker, if you will. Reason #2: Sigyn's character in the comics (from what I've seen by researching them; haven't really been a huge fan of comics yet, I'm afraid) was portrayed as being on Loki's side, and not converting him to "good." Reason #3: After the amount of time that has been spent examining the reasons why Loki is the way he is in the Marvel Cinematic Universe, this would be a serious cop-out.
As a side note, I'm not against recurring tropes in fiction; I just find it interesting how they are repeated over time. Oh, and I also find it interesting that Loki has the foundling trope in common with Superman, of all characters, although the result was different. Clark Kent was not told his Kryptonian ancestry, but the result of this was vastly different (other variables caused the difference, of course, but I still find it interesting, nonetheless).