In general I would like more voice acted lines for actions in the game. If Dota 2 has LoL beat anywhere, it's context triggered voice lines. (Like anti mage saying he didn't need the gold if you bought a blink dagger...because he already blinks practically the same range.) A lot of Dota 2 characters have lines for missing their CC or hitting creeps instead of players.
The hard parts of doing your own version is that your voice actors themselves are not on hand all the time. And to make sure they don't react strangely, ceeping the triggers clean and hard to spoof.
But FIRST BLOOD, ACE, and whatever versions of multikills that happens. that's fairly hard to spoof.
Have the character say the multikill lines as the timer runs out. And maybe a special version of ace for the delayed penta/quadra if the player chases the last one down with and without teammates.
Also need some line about getting killed by creeps after killing another player. MINIONS OP
I like the idea of a penta kill voice com based on how close to death you are. coming out with a sliver of health and having the character express correct for the personality disbelief.
Like in contrast between Darius and Draven.
Darius would probably express that it was close, but noxius will trample them.
Draven would say that it's worth the crowd reaction, even if some of it is his blood. His precious blood. D:<