It gets messy only if you let it. -_-
Its not fault of tool, that you dont use it properly. :-/
Here I'll speak in defense of an idealized large 'hotbar' scheme for a moment, just so you don't feel too demoralized Rag. This is what I'd need from it, like if Larian is unwilling to provide organization to the grid and I have to use it to effectively build my own UI. Or else just what I think a really cool D&D game might try to pull off at some point hehe.
First, things first...
1. I need to be able to save my Hotbar preferences via my profile. Call it custom hotbar settings or whatever you like, but the point is this... If I have to put in a ton of work into organizing things myself, and actually creating the structure of the hotbar layout, then I want to save that work so it can be used across multiple characters. I'm talking here about the structure, not the contents of the bar. If its modular and the grid can be moved around say or expanded to different sizes, we need to be able to save that out for later use.
2. For the structure of the bar I'd need to be able to divide or add some form of sectionality to the main giant hotbar, such that it's not really 1 single bar, but multiple bars or connected bars if you will.
3. For simplicity lets just say its Alpha-Numeric labelling, so I can have Hotbar A, and Hotbar B, C, D etc and also creating Rows of 1-10 for numpad or bind functions if desired within each bar. This would allow for rapid cycling not just on a keyboard, but also a controller. Anyone who makes use of keybinds for their gaming mouse or uses a padmapper to play a game like SWTOR will instantly understand the benefit of this to simplify a bunch of keys down to a switcher. It allows for a single button to be bound to the cycling function and then rotate between the bars. I'm not going to play this way, I use a regular mouse point and click from the heads up, but if they're going through the effort of making a modular UI, then accommodating convenient binds to the super mouse or controller too is optimal.
4. Ideally we'd be able to rotate our bars, so they could be columns rather than rows, if for some reason the player wishes that instead. Allow the player to free up screen real estate by going vertical if they like. Orientation left or right side etc.
5. Critically, allow individual sections/bars to be collapsed or expanded on the fly. Say I want one section for spells, one for potions, one for quick weapons, or whatever would be most useful given my Class choice. I might have one called Fighter 1, or Wizard 2, so I could say use the first for Lae'zel and another for Gale, whatever makes sense. But I don't need to see everything at once. Each bar should be collapsible into a single square, and expanded into a full row/column with ease. I'm perfectly fine for example, if the spellcasting interface takes the form of a hotbar that is micromanagable, but again only if I have a way to open/close to retrieve stuff from this hotbar at my discretion.
6. Allow us to stick all the other UI functions (the stuff that's not bars) anywhere we wish on the screen. At this point we're already using a grid system around the edges, so you might as well go the extra mile and let me change portrait locations, or reorient the mini map somewhere else etc, if for some reason that makes more sense for my layout loves.
7. Simply having 10 rows of 10, or 10 empty squares, where only 2 of these rows are visible at a time at the bottom with cycling is probably insufficient. Let me bring X number of rows up at a time if I wish, whatever is needed to get my quick read. If I have to page over constantly from a tiny tiny key, then it becomes even more inefficient than casting directly from a dedicated spellbook or using items directly from the inventory. At the same time if I can't reduce it to still see enough of my screen, that is a main issue. So we not only need to have a way to open and close the bars which are used less frequently or only at certain times, but also to set their dimensions.
8. For the icons which expand the squares into the rows, let us use icons similar to what we saw in the older BG games, just so it can have the sort of nostalgia call back perk. They don't have to be identical, but just some options that indicate general Arcane Spells, Divine Spells, Scrolls, Weapons etc. The ones already in use for inventory organization could be enlarged say and brought into something that can be dropped into a shortcut for the expandable square.
9. Allow us to assign all the various Auto-Add toggles which are currently Yes/No fields in the interface settings to individual hotbars instead. For example, Auto Add spells to Hotbar (A or B or C etc or 'None' meaning don't auto add them anywhere). I think if they actually put in the work on this, the actual goal would be to create Bars that are particularly well suited to particular characters or playstyles. So I'm not opposed to building or toolset type approach to the UI. It's just that I haven't seen it moving that direction at all. I think I may really be more in your camp than you realize. I can delight, but only if its creative and rewarding, thus...
0. Aesthetics! Most of the things I've described are the kind of generic transparency grids that we've seen in use for the UIs of other games for some time now, but that's not quite cool enough for Baldur's Gate! Or at least I don't think so, we should do better lol. Perhaps consider giving these grid bars the sort of flair you have right now. You know with the little baroque or nouveau flourishes on the boundaries that make it look extra Dungeons and Dragons, but add some more. Perhaps the design here could be modular as well, something more gargoyle stone in one set, or polished metallic, or nautiloidish for another, glass for yet another etc. Then have the bars themselves show different tints colors or patterns along their border. One might be reddish another more blue, that sort of thing. It's already in use on the current Hotbar, but I'm talking about giving the player some fun choices for that stuff. Basically the goal is to get some style points going for a custom UI. Just so it doesn't look so boring like the modular UIs of most MMOs. If it's meant to be gameful and more engaging, I think that is how to achieve such an aim. Get the player invested in the process, if they are expected to prune and maintain it. Make them love it the way Rags does, by having this be an expressive part of the game. Essentially like Character Creation, but instead call it "Dungeon Display." Everyone has their own style they love, perhaps I want it more pen and papery flair, with the chroma knocked back, someone else might want the interplanar vibe with that punched up. Maybe have one that looks more evil, one more good, or naturalistic vs urban city, with a bit of spread. So it can have a character all it's own.
There, that was the best I could do to express what I think a hotbar customization ideal might look like. 10 binds for fun UI ideas to play off I guess lol. I don't know that it's realistic really to expect Larian to go all gung ho with a UI hotbar deep dive. But if they did, I'd respect it. Not sure if you like any of those ideas, or if it's just taking the concept too extreme. But I think if the player is enticed rather than commanded out of necessity to build out their UI, then that would probably have more promise. It would be more gameful. If its your garden then you'll want to take care of it more. Right now it feels like pulling weeds up for the landlord though hehe. At least for me. I want it better
Best Elk