Nothing wrong with arrow keys, unless you're right-handed. I used them up to BF1942 and still wrecked people.
I used to use the arrow keys as a kid. When I got back into PC gaming as an adult, I found using the arrow keys extremely impractical, as the amount of buttons required to play a game greatly exceeds the buttons required for simplistic shooters of yore.
I think for a while I was trying to play BF:BC2 with the arrow keys for movement, shift for sprint, Ctrl for crouch, Numpad0 for melee, Numpad1 for reload, PgDn for grenades, etc. Just forces your hand into unnatural positions.
I vaguely recall playing some games back in the 90's that used the arrow keys for movement but can't recall which ones. If you've ever played the older Elder Scrolls games, you used the mouse for movement by clicking and holding on the edges of the screen. Now that is a pain. I'm glad you are able to map movement keys now with those games.
I was not the biggest PC nerd at the time so I may have missed other games that released at the same time, but Quake was the game changer for controls in my group. Literally went from using full keyboard for FPS games to using (split) wasd and arrows with mouse (which had to be enabled with +mlook in the console iirc!).
I think the mouse played the biggest conversion factor to was, too, as it gave most of us more comfortable space to work with rather than being crumpled up on one side of the desk. Not to mention with being able to use the mouse we didn't need the home/end/etc. keys as much.