And you're right, Alopex needs an arc to make her an independent character. Because if her looks are all it takes to "impress" people then that's a failure because most of the time Alopex is drawn terribly given only one artist knows how to do the fluffy visually appealing design of her.
If you ask me, I really wanted Alopex to be part of Karai's group. I mean Karai used to serve under Shredder's version of the Foot Clan, same as Alopex. And unlike Koya and Bludgeon, Alopex was the senior mutant agent among their ranks not to mention Shredder's personal favorite because of his love for foxes (Kitsune's influence).
But now all of a sudden you got Splinter directing the Foot Clan complete with entire radically different rules and code of conduct. I'm sure that such a shift is bound to be interesting in how it feels for both Karai and Alopex. The former is blood of Shredder and the latter was Shredder's personal favorite mutant assassin. You got something to make use out of.
But all we got is good old fashioned wasted potential.