Tell me why we need or do not need a wall?
Check your politics. To have a useful discussion here you need to check your politics at the door.
For transparency I am for a wall and secure border, I think 50-100B spent on border security is much better spent than foreign aid. We have been neglecting our border and our immigration system and we need to invest in it.
Make it easier for people who should be here to come and stay.
Make it harder for people who should not be here or circumvented the correct way to come here.