Yes, but she's shown to be very strong in some scenes and in some other instances extremely naive, bordering on stupid. That's what I didn't like; it seems like writers sometimes feel the need to tone down strong female characters with naivety and delicate flower behaviour. There is a middle point between the woman-child and the ultimate badass, but BW seems not to have found it yet (even if I love most of their characters, don't think I'm a hater)
Admittedly, there's inconsistent writing with some characters, and I concede that's true for Merrill. Look at Solas' dialogue to Cassandra where he seems to respect her, and then his dialogue towards a shemlen Inquisitor where he seems surprised about a good shemlen, or Sebastian coming across Clan Sabrae and expressing that he sees many souls awaiting "the Light" of the Chant, but then tells Merrill that perhaps the Dalish and Andrastian humans simply see the same divine force in different ways. It's even inconsistent in other ways, like how the writing for Isabela seemed to drift between respecting her sexual nature, and then mocking her for being sexual in other instances.
I think, if Merrill did appear again, that she wouldn't be the same young woman who was dealing with culture shock, since she's lived in a shemlen city for over a decade. I think that's meant to be reflected in Varric talking about how she's now leading the elves, almost as a de facto Keeper, and even protecting them from humans.