so instead of triangle = weapon switch, why can't it be triangle = transparent weapon menu comes up then you can pick one by pointing the brown townog stick in the direction of the picture of the weapon you want to select?
just an idea. and it wouldn't pause gameplay, could just be some small thing on the left/right of the screen somewhere (never actually played DNF, not sure how the UI is layed out)
now I mean of course this is just a concept - things would have to be considered like interference with movement (both player and camera) while selecting weapon (obviously you would freeze this as the menu pops up) .. guess you'd have to see if that ruins immersion or not ..
anyway that's just an idea. I'm no game designer lol. but isn't 2 weapons normally enough for FPS games anyway? good old <insert your favorite weapon here> and <insert secondary here>.