I’m not sure if the movie has room for it, but they have at least a little bit to talk about together, so it might come up.
That
said, I think part of the reason for killing Pietro was so that Wanda
could have a story without needing to tie back to him. With every second
of screentime being so important, they might not feel Wanda bringing up
something we already know, that can’t affect the story anymore–she
loves and misses her brother–contributes enough to her development.
She is young, and yes, inexperience plays into the way the Avengers treat her. But the writers have said it’s also a matter of fear-born condescension. You can see it in the argument Steve and Tony have over the pens. When coming to a head about what Steve feels is internment and Tony feels is due caution, Tony defaults into dehumanizing Wanda, Steve defaults into infantilizing her.
Including LEGO set spoilers and just about everything we know so far
The movie likely opens with Wanda and Vision staying together at this hotel in Edinburgh. After heading outside, they are attacked,
with the Mind Stone nearly successfully extracted from Vision,
leaving him injured.
But a timely rescue from Team Cap
allows them all to escape, and head back to the Avengers compound, with Vision still injured.
They meet up with Rhodey and Bruce and then head to Wakanda.
Shuri offers or agrees to help extract the Mind Stone (if the LEGO set is accurate) or help heal Vision.
Wanda and Vision stay with her as the rest battle Thanos’ army. It appears eventually things get dangerous enough that Wanda and Vision leave for the jungle, with Vision’s Stone still intact on his head, and Vision sitting on the ground, looking injured, and both know something is coming.
One last note, is that the Entertainment Weekly article mentions that Vision feels pain as the other Stones draw near–this could be inaccurate from them (because they do report some things wrong), but if so, it could mean that Vision was not damaged from the battle, but is reacting to the approaching Stones. Vision might be sensing them approaching, and that might be what Wanda is investigating here:
Wanda and Vision in Infinity War Trailer #2
Fandango Infinity War exclusive poster 2 of 5 (”Team Romance”)