I'm about to produce and start selling a grommet based range of joysticks. There will be two flavours: American will look and feel like a wico (but the look and feel are highly customisable), and Japanese will be smaller, lighter shaft, 35mm ball.
I don't play fighting games, and I've not felt a korean grommet stick.
So tell me if if you think a grommet might work for fighting games.
The obvious difference in characteristic to a sprung pivot, is the force/displacement curve near centre. On my stick, which is a precision fit between shaft and grommet, there is no noticeble free play region but the initial centering force is zero in the limit and then climbs approx linearly.