I really don't get this discussion.
Even if you can't remember which direction X and Y stand for, if you look at the map while moving you'll see which number is changing..
Also, if you are not sure if someone you are talking to knows it right, you can always just ask:
"So 35 horizontal and 27 vertical, right?"
What's wrong with a little bit of conversation..?

It's way better than being limited to 26 letters o,O
Or, in case you were not joking (because I hope you were) waaaaaaaay better than AA,AAA, B3 or whatever you thought of after the 26 letters of the alphabet run out.