I can't give simple answer yes or no, but I had some thought about heroes, especially about exp.
Exp points is not something new for rts games, first RA game already implement exp point for units. I heard many fans of SC want SC2 had exp points too, but for units.
I agree with exp points, but there's problem with exp points for units. Its a bit hard for me to explain, so I explain with example
If there's exp point for units, so units that frag more and more units will gain more level, which perhaps more hp, stronger damage, etc. But if only individual unit gain exp, such as wraith's kill so wraith's exp, than a problem will occur if a player often use minor units such as marine, zergling, hydralisks, etc that can be killed easily.
Example : A player with a squad marine engaged in battle against some opponent with equal numbers, he won with few marine left with some levels since scored many kills. Then the battle goes on, his opponent which defeated at first battle summon a ultralisk (if his opponent use zerg and jump tech), no matter how good his micro, the experienced marine would easily killed. Thus the exp point that gained by winning a hard battle gone.
I think many, many good sc players are players that utilize almost all available units, from minor units to major one. If exp point implemented to single unit, than player would often choose major units than minor, because exp point would easily gone if held by minor units.
NOw, this is my idea, i dunno if this a good one, you tell me.
Hero can be implemented to sc2 like wc3, but unlike wc3 hero will had less individual strength, except for some advanced hero.
My idea work like this
There's hero for each unit as representative. I took example for Terran. There's heroes that represent barrack units, there's also heroes for factory and stardock units. There's about 2 or 3 heroes for each representative, like 2 for barracks, 3 for factory.
Heroes from barracks units are minor hero, is a hero that had hp no more twice than the other barracks units but gain special ability. So the first hero won't be a super unit that can create chaos single handedly.
Heroes also gained exp from units that representative of the heroes. If a barrack unit score the kill, like marine, then the hero of barrack unit gained exp. If a stardock unit score the kill, like wraith, then the hero of stardock unit gained exp.
Hero had their own supply limit, like wc3 the limit grow each time player gained new tech lvl, but doesn't consume regular unit supply.
By using hero, exp point won't be gone easily, since it is held by the hero. So, player that often use minor units would still gain advantage from the exp from the minor units.