You are lucky to have got your 2nd legendary sword then XD that's probably one of reasons you tell about melee being bigger dps - most people won't get that 2nd legendary sword unless they get extremely lucky...
I just checked and apparently the biggest melee dps in the game is suzume I mentioned thx to her 150 atk speed while still having decent dmg over lvl. Pair her with a legendary sword and she indeed will improve your party of 2 melee/2 ranged a lot... problem is - my fighter class gear is only good for 1 person, and considering I want that person to tank - I use my best gear on fire tank and suzume just gets leftovers.
The ranged dps depends on which hero you got heavily, so I would rate the ranged heroes approxmately as follows on 3 tiers:
Tier 1: Heet/Roxelana - both are insane fire element ranged dps. Problem is - fire is weak vs water which has some decent foes.
Tier 2: Nuka/Althea - nuka is a hybrid of healer and dmg'er while still being decent dmg'er, she starts out with you, so no reason not to keep her unless you get very good heroes and althea is best and pretty much the only real healer in the game. Considering the healers have insanely low dmg capability - you won't want to have more healers than althea..
Althea's skill is actually one of the few you should really try to level up as much as you can.
Tier 3: everything else, those ranged are really better off not being used if possible, maybe only situational wise when fire is very bad vs certain map. But then again - it all comes up to your randomness and who you got... if you only lucked out to get a total of 4 non duplicate heroes including starting one - you don't exactly have a choice at all.
I am not counting micah in, because I assume she is the only legendary tier hero we have and you won't ever get her pretty much, but if you do - she is the best of them all and should probably be included in any party.