I disrecomment custom commands buttons that cast blizzards, stormbolts and such targeted spells. Remaking the targeting is far to much work and will perform bad in online play.
Self casts are good.
One can make a custom frame with all the stuff: icon, clickable, cooldown, tooltip, charges ... . Hotkey one would do with the oskey events.
It is easier to hide (some) default commands with a imported file units/commandfunc.txt (like mentioned in that link from Pyrogasm). Then you can have upto 12 spells, when you hide all default commands.
in player=hero maps:
Patrol & Move are unneeded (right click still works to move around).
Attack, Hold & Stop are useful.
There are practical problems with many skills on a hero:
unique orders. Or do channel spells. (otherwise the game might cast some other ability)
more actives -> more mana usage & more time needed to choose targets.
making 7+ skills for each hero takes much effort.
basic attack needs to be weak, the hero needs time to use all that skills and it now needs to be worth using all that active skills.
^^ look at custom hero maps, when the map does not force you to pick many actives players tend to pick a small amount of actives and a big amount of passives.
I once made a custom button system, which could have many many buttons. it used the wow targeting, you select your target and then everything is casted onto that target. Was far to much work and I never used it outside of the demo map. I choose this other targeting because with many actives it is annoying that one needs to confirm the targeting everytime. if you want to take a look, i discontinued that project (and I will not continue it), the demo works in Warcraft 3 V1.31.1, no idea about current version.
I liked making that system

,learned some stuff making it. But imo it is not so useful in a real map (to far away from warcraft 3).
Custom Ability Button System (CABS) is a custom UI that is meant to be more compatible for maps in which the player controls only 1 main unit a hero. It features a custom interface to activade default and vanila Abilities of warcraft 3, as long they are setuped inside the system. One can let...
www.hiveworkshop.com