I would like more modability but, I do like the engine, though other games look just as good on other engines and, though I haven't played them, I hear they perform better or, at least as well.
The biggest issue is making the game compatible with older systems, be that consoles or computers. to make it use less sytem resources, you have to cut content, functionality and graphics quality. Unfortunately not doing that means you have a much smaller customer base and, have to sell the game for more money per copy to the customers that can run it.
What if it required a 6 core 4.0 CPU
4GB VRAM, Nividia Ttitan or better
16 GB system RAM
How many would have the machines, or be able to afford the machines to run such a game? Yes I have one that exceeds even that but it's a 5000 USD computer. Not many would spend 5 grand just so they could run a game. Hardcore gamers that need the power to run multiple games at max quality with 60+ FPS consistently yes, but not the casual gamer that just wants to play one game in their spare time now and then.