If you played HC in previous titles, you got used to being able to pull up the full map.
Perhaps this is intended to be second screen functionality... but for now...
... I miss it.
I think you can in Core, at least I'm pretty sure I've done it.
I know in HC you could sit in a corner and watch unsuppressed users pop up and call out positions. I've actually done that a few times and it might not be as effective as a mini map but it still works pretty well. That's my guess as to why they removed it.
I never really used to the full map in previous COD games. Although, It would be nice to pull it up by a quick peek using the start button or something along those lines.
Prior to BO2... that was the case. In BO2... enemy players didn't appear on the the full map except when there was a UAV.
You can't even pull up the full map in Ghosts.
It's not a big deal but I used it all the time to gauge where my team was and get a feel for when the spwans might flip or where the other team is based on team deaths.