Part of the issue is we're limited on system-installed fonts and not any font. This is to make the assets cross-platform should they be uploaded to the DLS. The non-system fonts, being those found on foundry websites such as DaFont and others, would mean the asset would be missing the fonts if the other users can't download the fonts, besides, some actually are copyright-protected and can't be shared.
Creating a 3d-sign such as the Valero sign above is all well and good, but that has its own issues such as the mesh needed for the letters, and yet again more polygons, LOD, and all that goes with that. The other thing too is each one is custom for the asset, making them a limited item.
So, what's the alternative? Use the existing station signs. Some hang, some are on posts, some are small and some are large. There are even signs that support multiple lines and those too come in various sizes. These at least can be customized, text-wise anyway, or can be cloned to change the color on them. In that case, you'd have to change the color of the font as well so it's not invisible or difficult to read.
And finally, the only other thing you can do is to customize each asset with its own painted sign as you've done. Nothing difficult, just one more option.