The idea is to have the option to set a combo of weaponskills to a single button. It would mean that I could set a path of weaponskills that would actively switch the button on the hotbar to the next weaponskill in line until the "combo effect" wears off (via use or duration), at which point it would revert to the starting ability.
Using GLA as an example, let's say I set "Fast Blade" as the starter, and fill in "Savage Blade" as the next attack in line, followed by "Rage of Halone" for the third attack. When I use "Fast Blade", the button switches to "Savage Blade". From here, if I use "Savage Blade", it will switch to "Rage of Halone", but if I wait out the "combo effect" and it wears off, the button reverts back to "Fast Blade". Additionally, setting another button to "Fast Blade" -> "Riot Blade" combo works the same, being able to use "Fast Blade" on either button to start-- button 1 moves to "Savage Blade", button 2 moves to "Riot Blade".
EDIT: I should make it clear that what I'm suggesting is not for simple macros that change the icon as it goes-- you would still have to hit the button again for the next hit in the combo, and you would be able to use other abilities on different slots of your hotbar in between your combo, or instead of them. You'd still have to think about what you do next, but your combo is set to a single button (multiple presses, though) specifically to preserve space if you need it and it would be restricted to combo actions/weaponskills, not full rotations of abilities.
Example of what could be set as a same button combo: MRD~ Heavy Swing* > Maim* > Storm's Path*
Example of what could not be set as a same button combo: MRD~ Heavy Swing* > Berserk** > Maim* > Internal Release** > Storm's Path*
* These are the weaponskills that make up the actual combo
** Abilities unrelated to the combo of weaponskills