I think Tekken is 4 buttons, and Neo-Geo is 4 buttons, so I'm not sure your numpad rant quite applies. I've seen some Neo-Geo layouts with a 2x2 layout instead of the traditional swoosh, so I think it would be ok.

Personally, I've got lots of room, so if I were a multi-cade person, I'd build out different machines for different layouts.

Something for classic single joystick games with two buttons on either side (although that might not be perfect for everything, some games had three buttons on one side). Something for trackballs, hopefully a layout that's reasonable for missle command and two player marble madness. Something with three buttons each for four players (guantlet/turtles/nba jam). A 4-button Neo Geo layout, which might be enough for the two player two and three button games too; would need to try and see. A 6-button 2x3 layout. If I played MK, their 6-button layout with run, although since I don't play MK, I might put the pre-run games on the street fighter layout with the column in the middle both being block; definitely saw that in arcades.