Upgrade the walls, or provide a different art and alignment for them?
If it's the latter, yeah, it's certainly... "annoying" to say the least if you do plan on utilizing a different orientation (for example platforms) - especially with their building prevention "radius/collision". Didn't test it in 0.1.3 as of yet, but if one of your issues is the collision part as well, atleast you can "cheat" it a bit - move your cursor over a place you can build on, pause (escape) the game, move your cursor where you want to place it and do so, then unpause and repeat until you build all you want, wherever you want it.
But yeah... those walls are a pain in the ass when wanting to include other stuff. (Can still be made to look acceptable, but is a pain to work with)