So using ammo packs was a cumbersome ordeal or so I am told. I never used them. The good news is, regardless of my lack of plight, I had an interesting solution that required no new special button configurations or the removal of dancing. So there you are. You just ran out of your special ammo and there is this crazy Hive/Fallen/Fill in the blank who is hunting you down. Rather than running away and hiding in a corner, and hoping he doesn't chase you/find a way to shoot you anyways, while trying to use an ammo pack, it could be as simple as pressing and holding the reload button, similar to how the heavy weapon is selected, and it could use one of the associated ammo packs, if you have have any. Since it would be contextually sensitive to the weapon selected, you could with just one button hold apiece refill all of your different ammo types from ammo packs, simply by cycling through the weapons and pressing and holding your reload button.