did the original qbert cabs stick only move in diagonals?
It was a normal 4-way (like pacman), but rotated 45 degrees so it could only do "diagonals", even though
to the joystick it was still up, down, left & right. This is also why mame calls the directions as such.
So yes, and no.
FWIW, you don't even need the map anymore. Leave the u360 in analog mode and let mame do the exact same conversion but in software. Mame modeled the analog to digital joystick conversion from u360's; both have 9x9 grids, a diagonal 4-way map, game specific remapping, etc.
So you just need the u360 and a semi-current mame.
OTOH if you use other emus, you'll need the external remap app.
Does this work for 4-way, 2-way games as well? (Using Mame .122) I would like to try something other than Mala with my U360 but really like how Fatfingers mapping works with it. Non 8-ways were basically unplayable with my U360 until I got his Mala plug-in configured.
Yes. Mame has automatic default maps for 8-way, 4-way, diagonal 4-way, and (sort of) 2 way games. If the u360 is in analog mode when mame starts, mame will use the correct map. You can also make your own maps if you don't like mame's default ones. More info can be found in docs/config.txt, under -joystick_map option.
I'm at work so I can't try it out myself.
I don't know what you're talking about.