I Try To Keep My Mouth Shut Most Of The Time
With all due respect, Lunaran, I could not disagree more. A while back I posted a comment with some thoughts about this on Joe Wintergreen's video regarding the topic:
https://www.youtube.com/watch?v=b64lKqbbaUM But I'd like to elaborate.
There's a difference between "building BSP architecture" and "using BSP-style tools to build mesh architecture". HammUEr does the latter, from the sound of things. No one is advocating a return to BSP brush based engines, only that simple, intuitive, accessible tools like those found in Hammer be made available in modern editors. Hardly a non-trivial development task, but with million-instance foliage rendering and hundred-square-mile procedural terrain handled so well, I'd think this is comparatively straightforward.
For more than a decade I've heard your arguments thrown in my face with an eye roll and exasperated sigh every time this comes up, and they're just as insulting now as they were ten years ago. Working with 3D applications is as sluggish as ever when you have simple, low end needs like mine.
It's like a tractor trailer: When you're a professional driver, delivering tens of thousands of pounds of food to a supermarket from a distribution center, the vehicle makes sense. You have extensive training, and the trucking company handles operating costs and maintenance. But when you're an individual who just wants to take his family to the grocery store to pick up a few things for dinner, a minivan is the better choice. The commercial truck holds much more cargo, much more weight, is engineered to a higher standard, and will go for literally millions of miles when properly cared for. But the thousands of dollars a week in fuel, the vehicle height, weight and turn radius limiting the roads one can travel, noise and idling ordinances, and difficulty of parking make the vehicle wildly impractical if you don't need its power. You're not simply ABLE to use its capabilities, you're OBLIGATED to.
A more fitting analogy, though, might be "Why do you need Blueprint? Do all your game logic prototyping in Visual Studio! In fact, forget high level languages like C++ and do everything in Assembly, that gives far more power."
We're not earning crane operator licenses, we're not joining the military, this isn't some delicate responsibility you risk handing over to people who might get someone killed through lack of professionalism. Exclusivity of game development as a whole, or even just mapping as a part of that, to only the handful of elites who can work in The One True Way is not something I'm comfortable with. I don't care if Bob Ross' students only paint "motel art", they are and should be able to create simply because it makes them happy, without having to get an art degree before being granted that privilege.
I understand how the tools came to be the way they are, and if they're only ever going to be targeted at professionals, or aspiring professionals, there's no problem. But with engines like UE4, Unity, and Source 2 (which I might add seems to do things the way I want, see the Dota 2 Workshop Tools Alpha version of Hammer for reference) being lowered in cost and opened to a wider audience, I don't think it's unreasonable to suggest less professional people could have a bone tossed our way with regard to polyhedron editing interfaces.