So to disambiguate, there are several problems, and a few related factors, which aren't the probem in and of themselves, but either cause directly or by proxy the problems in questions.
So we have these factors:
1. Ranged and melee attacks are functionally identical in stat and skill factors, except that ranged attacks may be done at any range, instead of just range 1 or 1&2
2. Ranged weapons have a top and bottom end (DPS-wise) which overlaps the melee weapon's usual viable range
3. Ammo is limited in total supply, which keeps "only use a ranged weapon" non-viable early and is difficult to reliably do late without god support.
4. Nonthreatening monsters can be safely killed throughout the game using any weapon, not just whatever you have trained the most, and there's a lot of nonthreatening monsters.
5. Using a ranged weapon creates overhead in the form of having to retrieve your used ammo, which can't be 100% automated with the current UI, as there's no way for the game to know if it would be safe to retrive your ammo.
And we have the following problems:
1. UI problems, weapon swapping: Incentivizing using one weapon at range and one for melee-range isn't really a problem in and of itself, as long as doing so causes minimal overhead, automating weapon-swapping is plausible, however since presently switching weapons costs a turn, there's a subset of people who will want direct control (There will always be situations when you'd prefer to make a different choice). The present weapon-swapping shortcut, if used properly (' to swap between a and b) works, but isn't a complete solution for people who would prefer more automation, a more complete weapon-swapping LUA script is likely possible, but would be sometimes suboptimal.
2. UI problems, Ammunition pickup: While you can auto-explore to pick up ammunition, auto-explore is frequently suboptimal, an 'autopickup' key that basically did 'autoexplore until there was nothing to left pick up' would probably help bridge the gap. As pointed out, removing ammunition would also remove this problem.
3. Balance problems: Presently ranged weapons are literally a superset of melee, they are just flat-out as good or better than melee *other than* ammunition, having ammunition requirements does contribute to tedium, but it doesn't *only* generate tedium, it also provides a backstop against ranged weapons being absolutely superior to melee ones, it's probably not strong enough in the balance aspect when compared to the tedium aspect (Although if you obviate the UI concerns the tedium goes down significantly).
4. Inventory Management problems: This was reduced somewhat when most ammunition lost branding (also when it lost enchantment) throwing is still a significant problem
5. You're incentivized to avoid firing in such a way as you might lose ammo: At least until your ammo supply is large, you have to pay attention to trivia like when you might miss and toss an arrow into lava/deep water, but you can't simply automate stop at first target always because it's also optimal to fire in such a way that your arrow will get chances to hit more things in corridors, particularly against stuff like bees in corridors. (Which means you cant effectively always choose one option or the other) this is a micro-optimization, in that it will have minimal effects on your success, but it still has a clearly superior choice, applying extra cognative overhead for something that's low-impact.
For the proposed solutions and some counterarguments:
1. Remove ammunition with no other changes: This basically just breaks melee weapons as a viable choice, it makes a subset of the game completely superior, which by definition reduces the flexibility of the game, if one path is inherently superior for all applications, then it trivializes player choice, it's pretty clear this isn't going to happen even if people are opinionated about the game not being very balanced to begin with.
2. Make ranged weapons very strong, but very limited: This pushes ranged weapons directly into evocable territory, while evocables are currently very strong, having an alternative which is "the same thing but trains a different skill" doesn't actually contribute to the game in any sort of interesting way.
3. Make it impossible to fire adjacent: While this does serve to distinguish ranged from melee, since there's few reliable ways to create gaps, you're even more strongly incentivized to have a melee swap. Additionally if you make monster and player weapon use the same, then ranged-weapon-using creatures can be completely neutered by standing next to them, if you don't then you have a weird discontinuity which is difficult to explain in an intuitive fashion.
4. Destroy all ammunition (and increase ammo generation to compensate): This addresses one UI concern, but there's no way to generate ammunition in a way that preserves the existing balance, either you generate too much early and have unlimited ranged weapons, or you generate to little early and effectively degenerate to weaker evocations. This was prodded at fairly seriously and in the end was thrown out.
5. Make ranged weapons do decreasing damage as you get closer: This is like a watered-down 3, with the same (if less strong) drawbacks.
6. Make ammunition not mulch, but be incredibly rare: this is similar to 2, but serves to distinguish ranged slightly from evocations. Unfortunately it does nothing to the UI problems, and actually excaberates the 'don't lose your ammo' problem. Also it makes it much harder to use, as you have to find at least two items (launcher+ammo) making it uncommon indeed that it'd be worth investing skill points into
7. Removed ranged weapons and ammunition and everything related: I mean I guess it does get rid of the problems
All of the solutions I've seen so far have drawbacks and there's no clear consensus as to what's the thing that most needs fixing, particularly if the solution makes some other part of the problem worse.
I'll suggested the following, which probably has as many holes as the other suggestions, but at least it's another proposal:
8. Make ammunition virtual, launchers have "ammo" charges, but the max a launcher can hold depends on your current skill (so you could have up to 27 arrows in your bow at 27 skill) launchers regain ammo by resting (I'd flavor it as you actually creating the ammo yourself, but that's not really material), not with experience, and only while wielded. This doesn't really address throwing at all, I'm not really sure what to do about that.
Personally I don't care much about the weapon-swapping nor pickup issues, I don't like how many slots throwing takes up, and I don't really like that ranged is basically a jumped-up melee weapon once you get a reasonable ammo supply.