Within the 3 ammo rotation in Stormblood, wildfire ammo went like:
- (no initial proc) > QR (1) Split > Overheat > (0) CD > Reload (3) CD > (2) Slug > (1) Clean > (0) CD > (0) CD
- (slug proc) > QR (1) Slug > Overheat > (0) CD > Reload (3) CD > (2) CD > (1) Clean > (0) CD > (0) CD
- (clean proc) > QR (1) Split > Overheat > (0) CD > Reload (3) Clean > (2) Slug > (1) Clean > (0) CD > (0) CD
Which was aimed at maximizing the potency amount crammed inside WF, which required ammo to actually work on Clean and CD to gain that 25 potency on every ammo-ed skill. The rest of the time it could happen that with the other mid rotation reload you had already one proc ready, so an ammo overwrite was inevitable yes.
Even in HW with the 5 ammo where it sure was more awkward since... 5 ammo, it was still used as a boost under WF to get the most potency possible in conjunction with QR.
People had problems using ammo and proc priority right perhaps, but that's the same problem with RDM and DNC where overwriting stuff is also a reality. If they brought back ammo I'd honestly consider replaying that class again but I have no illusion that for whatever reason procs have been given to other classes like RDM (that even transformed acceleration into an ammo/reload tool) and DNC.