Personally I think that Maya’s character is still has a purpose.
- She could teach and/or guide Ava
- She can help Tannic to study more about sirens
- She still can be a good vault hunter (plus she can team up with Krieg)
As for returning her to life or recreating her… we already bring one character back from the dead in side quest so technically it’s possible.
I clearly can see the DLC where Ava seeking redemption and trying return/resurrect/recreate her teacher. It will make Ava a more lovable character and return Maya at the same time. I see this as a win-win situation.