During fighting with malfunctioning Smart cast plugin by KYSXD , i come to an idea:

what if the spell that require pointing target, was immediately activated when you press the keyboard hot key, without the need to press left mouse button?

by this time for sure somebody think about it. Probably its already in other games (sc2? i never really play it).

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"so what do you want?
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is there some plugin/mod with to BW with it? is this in Starcraft 2 (but i dont want to dl this gigabytes just to check it)? maybe its in some other game?

I would like to test it.

In Heroes of the Storm there's a feature like that.

Spells can be set to (if possible) activate on key press/release and target whatever is under the cursor.

I think is also in SCII, I don't remember at this point.

About a plugin... that may be an interesting challange. I'll take a look.

(Just a small correction)
SCII has an "Autocast" system. When activated by a right-click toggle (on the button), the unit will freely cast self/single-target abilities when either idle or attack-moving. The most prominent examples are Stim, Snipe, Magrail Munitions, Shadow Fury, Heal, Repair, Nano-Repair.
Something like this is probably more possible than the Keypress Smart Cast system. First is the fact that medics always perform healing automatically. Secondly, I've seen some siege tanks affected by the "Order: Attack" trigger automatically use Siege Mode when engaging an enemy mob. With EUD's, it is currently possible to modify some of the basic actions of units, although overwriting these may result in weird behavior, ineffective combat performance, or game crashing.