It's also possible that range boosters are too powerful right now, as once you get a few of those you can take out huge numbers without them getting to shoot back. Maybe a weapon should be limited to one range boosting item, or range boosts should be more "expensive" on an item so range boost items cost more power and have less other stuff on them, to reflect how strong they really are.
That's not exactly the same issue as the health scaling, but I think it's one of the reasons people are finding things easier.
Range in general is a bit overpowered in some ways.
The thing is that you dont need a ton of range boosters in order to out-range enemies in many cases; but if the enemies had a tendancy to have MORE range than the player, the game would become entirely about stealth, as that'd be the only way to stop them. This is one of the issues in general when you have ranged attacks in a roguelike, I've seen it before. There isnt really any good way around it. Particularly when there isnt anything that has any movement abilities or anything of that nature. There arent, for example, any bots that have the ability to charge at you and suddenly be 5 tiles closer. Or teleporters, or whatever.
One other thing to consider though is the number of enemies that the player can effectively target at once. Most of the time, the player is only hitting one enemy at a time. If you're killing off each foe in one hit, and there's only so many of them, then yeah, your extended range is going to flatten them as they keep coming. It's one of the reasons why I've suggested health/shield/whatever boosts to enemy bots, as many of them have hardly any health. But, greater numbers can also mean something here, because again, you can only hit so many at once in most cases, particularly in cramped areas. Having them coming from multiple directions at once is also important, as it is in many roguelikes.
The real question to me is: How difficult are players finding the game to be, on their chosen level of difficulty? If too many that are playing it are finding it to be a bit easy, then in that case, something is off. It might be worth inquiring about this.