I realize that I'm one of the last people that might be expected to advocate for keeping borderline-superfluous keys inside a Job, but I feel like Refulgent Arrow still serves a fairly distinct purpose for several reasons:
  • It's not literally the same thing as Burst Shot — combos proceed very predictably, and breaking them is (hypothetically) always irrational. Procs occur unpredictably, and needing to react to them is essentially what makes it a proc instead of a combo.
  • It serves as a check on Barrage usage — Weaving Barrage incorrectly will waste a proc.
  • It serves as a minor check on player awareness to avoid overwriting a proc inappropriately, similar to choosing the correct combo continuation (although my opinion about the actual gameplay value provided by many of the game's current combos is a separate topic).
That said, if the proposal is to remove Bard's proc gameplay and convert it to a more standard MCH or DNC-like combo system of Burst Shot → Straight Shot → Refulgent Arrow, that's an interesting idea.

But I personally think that as long as Refulgent Arrow remains a non-guaranteed continuation from Burst Shot, that it would be unhygienic design to make it an automatic conversion, because at that point there is no reason to have a proc at all, since it requires no thinking and instead becomes frustrating (ie, "Sometimes my filler button randomly does more damage, but I have no control over it").

These are weird and subtle psychological hair-splitting considerations, and I'm not surprised that everyone views it slightly differently, but that's my take on it: the current chance-based design means that there is a psychological purpose to needing to choose a different key when the randomness occurs.

If the argument is that the "specialness" of Refulgent Arrow has been watered-down to the point that it barely feels exciting any more, I can definitely understand that perspective. But in that case, I think that it would be better to just give Bard a real combo, rather than a "fake proc" that the user essentially has no control over either way.