may i ask? looks like there are some important npcs in this game besides those who i met during quests, right? and if i play with range weapons only, so i have low chance to capture anyone, then i miss some content?
You can certainly miss a lot if you don't capture enemies. There are some very nice unique girls you can capture in fights. Not to mention selling or auctioning random captives is a very nice source of income.
I recommend using melee more. It may appear not very efficient at first when you have to waste a turn to get close, but that is easily fixed by having at least 80 melee combat, which lets you start the fight in the first row. 80 dex can do that too, Enya being a prime example of that, but obviously spending your daily training sessions on combat skill is much more preferable in the beginning.
While ranged weapons do not have another stat that increase their damage, melee weapons do and it's the strength. With enough strength even a whipping cane does a lot of damage and it guarantees a capture if only it is possible in the fight.
Melee weapons also have Power Strike that increase their damage at the small cost of hit chance and you can use it in the same turn unlike Aim. Some weapons like great swords or axes have additional extra damage on power strikes on top of regular power strike bonus. A party of great sword/axe users with 100+ melee/strength can easily clear last arena fight killing both cybercannon enemies before they even get the chance to use their weapons. It doesn't take that long to train 100+ in both with a dojo, you mostly don't fail trainings until 90+ and even then failing is not common.
The only con of using melee weapons is that in some high tier fights enemies can have a lot of dex, usually only one enemy per group is hard to hit, but then R-55 revolvers come to the rescue with their hit chance bonus, .50 ammo is not that expensive and you already start in the first row anyway.