The ctrl-up/ctrl-down shortcuts for prev/next pattern should be the same in pattern matrix as in normal pattern editor by default. Those shortcuts currently zooms the matrix.
I don’t agree – the arrow keys all move the selection in the matrix, just as they do in the pattern editor. It’s just that the “selection” in the matrix is a whole pattern in length, not a single line.
There are global shortcuts for prev/next pattern but they are not assigned by default. Once assigned, they will override all other Control + Up/Down keys…
-> Preferences -> Keyboard -> Global, search for “go to” -> “Go to Prev/Next Pattern In Sequence”
+1. This makes it hard to audition your changes.
My suggestion is motivated purely by what is intuitively easier and better for the workflow.
I am grateful i can change the keys, however 
EDIT: I just realized how it works now, it’s not harder, it’s just different.