Best software package for modern, squad-level tactical mapping?

[Sam101]

'I'm technologically capable and dont shy away from complex interfaces'

Ok then I recommend Blender/Krita/Gimp.

You can make buildings in Blender, render them, then paint them in Krita or Gimp.
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[Sam101]

And for ground textures, an easy way is to find good textures and pattern stamp them:
k5.jpg
Of course, making it nice an refining it would take some time, but that's what I would do.

[Falconius]

'I'm technologically capable and dont shy away from complex interfaces'

Ok then I recommend Blender/Krita/Gimp.

You can make buildings in Blender, render them, then paint them in Krita or Gimp.

It's a good suggestion, however:

My main issue is a lack of artistic ability and so will be reliant on the graphics the software includes.

Renders such an approach daunting. That said Josh, you can always buy (or find free ones) pre-made files (objects, houses etc.) and arrange them in Blender to your liking, and render things that way. I do believe that one of the Campaign/Dungeon software sounds more like what you are looking for though.