You want to maintain the same output pattern as your OEM fog lights, while producing more overall output. Distance isn't as big a concern since it's not a primary driving beam, but having some width will make them more helpful in foggy conditions.
You are correct in that most LED replacements do not utilize the OEM halogen reflector optics correctly, that is, until we released our SL-series line of LED replacements. They do an exceptional job utilizing the factory optics, produce more output, with no added glare. Here's an output comparison we just did with a WRX this week:
Notice how the SLF has the same foreground pattern as the OEM halogen bulb? That's due to the fact that our engineering team placed the LED chipset as close to the position of the halogen filament as possible. It was done using a sophisticated optical modeling software program.
Two other advantages:
1. Cool white ( SLF is 5,700K ) will match OEM LED DRLs & HIDs nicely for a huge cosmetic upgrade
2. Yellow fog lights, if you want that look, ours are a great looking yellow! (Designed by our lead electrical engineer who has a 2015 STI)
Thank you for asking!