Just eliminate all those annoying distractions like forts, lanes, minions, mercs, and the core. In fact, instead of unique maps, make one where everybody has to stand in melee range. This will guarantee every hero’s presence in the team fight.
More seriously, one of the things that first attracted me to this game was the ability to make a difference that didn’t rely on directly beating the tar out of the other side. It’s a little disappointing to see the heroes that previously focused on that get moved more and more towards being no more disposed toward it than any other hero.