OK, I continue to work on pure speculation (even though my speculation seems to have a pretty good track record in this thread), BUT...
From the intent we're seeing, it's improper to think of this new "macro set" as a macro set per se. As stated earlier, it will pretty much always be displayed on the screen, in contrast to having to hold Ctrl/Alt or R2/L2.
And, with the apparent aim of making it more resemble XIV (again, my speculation), you should instead think of this "macro set" as a replacement for the "Action Command Window" (that is, the context-sensitive menu that currently pops up in the lower-left). Instead of having something from which to select "Disengage," "Ability" or "Magic" from, you will instead have a row of pretty icons that you arrange and customize yourself.
The icons will be navigable with the d-pad but, without the menu nesting present in the current UI, it won't be as efficient as clicking with a mouse.
Of course, it would be really nice to have some sort of mock-up without having to wait until the end of June so we can all know what the heck we're talking about!
/subtlehint