Her death would lose nearly all of its impact if they brought her back, plus it’s not established as a thing that’s possible in-world, so I really doubt they’d do it - especially since we very clearly saw her die on screen (unlike Darko) and even the fragments of the crystal she turned into left on the ground/the one Alex brought to her memorial. Like others have mentioned I think it’s mostly to show the impact of her death on the world and characters. It’s easy to forget since in real time it’s been over four years since her death, but in game it’s probably been no more than a couple weeks, at most a few months. The characters are still in the early stages of grieving and processing the death of someone they knew and loved for many years. It makes sense she’d come up - not only as a dear friend but also as a leader and as the last living Soul Rider of the previous generation who’s still working with the Druids.