Why isn't RDM's Riposte combo tied to one button?

[Seraphor]

My issue with this, is that if you consolidate a combo, it’s no longer a combo, it’s just one skill you spam.
You may as well remove the other two skills and give it a trait that increases it’s damage with successive hits up to three times.

People are complaining that DRK’s burst is just Bloodspiller spam, this would make the entire job just spamming two skills, one for regular attacks, another for the burst.

Personally, I like to know where in the combo I am. The GNB example is spot on. When 3 gives me my ammo, I need to know when I’m hitting 3 so I don’t overcap.
If it’s all the same button, I’m much more likely to lose track of where I am in the combo.
Then you have positionals, which press of 1 will require me to be at the targets rear?

Just because you always use those skills in succession, doesn't mean they're not their own unique skills, and it's not only combo skills that you always use in succession.