I got those 194 360-degree bulbs, too. In fact, your post made me do it.
They're indeed extremely bright as BRZ's front side markers, but the exact same bulbs aren't all that effective as Impreza's front side markers. These little enclosures don't have room for back reflectors, or the reflectors are literally the size of the bulb itself, so unless the bulb is translucent, like the incandescent bulbs, all we see is the LED chips that are pointing outwards. The ones pointing the other way don't contribute at all to what we see.
I also bought their red 194 and put them in the rear, and they're insanely visible in the Impreza, but just okay in the BRZ. The reflector design and the bulb orientation, or rather the location of the actual emitters, is paramount to these LEDs.
I tried to illustrate this by combining a bunch of photos I took with the cars parked side-by-side in my garage.
The rear side markers illustrate this best. On the Impreza, the entire housing is lighted, and it's bright no matter which direction I look from. I think at least 4 (out of 6) emitters are really contributing here, with the remaining 2 also contributing some. In the BRZ, maybe 3 are contributing somewhat, and their angles aren't ideal for the housing design.
I'm thinking even one emitter placed just right can be more effective in some cases over 6 emitters in a generic pattern. Unless they start making custom bulbs for individual cars, we'll just have to get by with what we get.