Hero arena: Balancing melee and ranged

The problem with ranged characters in hero-based maps is that their range is too short to do the "guided arrow/FO from 3 screens away" thing effectively, so they are basically just melee characters with a nicer looking attack. This results in the typical boring "gameplay" of hero arenas that consists of clicking on the enemy and hoping you got the more overpowered hero.

My "amazing solution" was to greatly increase the range of my ranged heroes. The shortest ranged one has 1500, the longest ranged one has 5000. This does allow them to shoot without getting hit back, as intended.

The problem is that now melee characters get hosed, as they are completely unable to get close enough to attack. I have no idea what to do against it.

The map has a lot of lava, which causes damage, and I thought melee heroes would be able to take shortcuts through the lava and not suffer much from it, while ranged sniper heroes would almost die from looking at it and be forced to take the long way most of the time. Doesn't help, because heroes get more HP when they level up, and at level 6 or 8 or 10 the ranged heroes can pretty much ignore the lava as well.

I tried making some skills that would hose the ranged hero when the melee hero does catch him. There was one debuff skill that made the target start spinning around when attacked, and another one that made them hop up and down. Doesn't work. If you manage to catch the sniper hero and swing once, you win, if not, you lose. Hardly fair.

I tried adding some skills to melee heroes to stop ranged heroes from running away. The biggest, highest damage, slowest melee hero has a skill that summons the target enemy to him and automatically attacks him. The minotaur does the opposite, and teleports onto the target. Doesn't work. If you don't pick those specific skills, you lose, if you do pick them, it turns your melee hero into a ranged hero too. Get within range xyz to cast your skill. It takes away the melee part of it.

I finally tried adding skills that would force the sniper heroes to come out and kill faster. Sniper skills obviously do less damage than melee combat skills, so if I could ensure that the sniper hero would slowly die if he keeps running away and casting from 5 screens away, it would make them come closer and use more powerful short ranged attacks. But casting thunderstorms to strike down snipers at the other end of the map makes you a sniper hero too, and a more powerful one at that, as you'd have more hit points. And god forbid you'd have five of these heroes "fighting" each other, ie. hiding in the corners of the map and spamming thunderstorm or lightning sentry at the other corners.

I'm completely stuck. Should I give up all hope to balance the "amazon" versus the "paladin", or can anything be done?

make a ranged damage reduction skill based of mountain giants damage reduction, make several copies of it and assign it to the heros......
eg the slowest moving hero would get the most effective ranged dmg reduction....