Looking better, but that's 2d decoration. You'll also need 3d decoration as well, in the form of brushes and props. I kinda explained it in this picture: (1) This is a simple wall. And it won't do, at least in large areas where everything looks the same. You need a form of decoration to make it more interesting. (2) This is better, a prop vent with some decals. But it still wont cut it. (3) Adding different effects and interesting architecture makes it even more interesting, like dustmotes, sprites, particles ect. (4) But it's up to you to determine if it's fit for the map. A warehouse doesn't have modern art in it; nor a bar, it's shape being simple, but realistic. If a building actually IS something, like a crane that's in reach of grabbing containers for a harbour, or a cafeteria in an office workspace. If people know what it's supposed to be, it'll be a lot familiar to them. Instead of saying: "That building is under attack", they'd say: "The warehouse is under attack". More importantly, it's not the shape or looks of a map that makes it good, it's the fun the players have. If a map is well balanced, it will always be chosen instead of a pretty, but unbalanced map.