No, I don't think you have made a mistake, in general. But there certain plants that do better in lean (not rich) soil.
-Russian Sage
-all Penstemon species (most hybrids do fine)
-most alpine plants
-cactus and succulents (like sedums and hen & chicks)
-many prairie plants, including pasque flowers, brown headed cone flowers (Ratibida spp.), sunflowers, short and mid grasses,Prairie Smoke

I'm not big on sages, but my guess is that they would be included.

Putting potentially invasive plants in poor soil can help curb their growth. I've done this with Obedient Plant (sorry, I can't remember the botanical name) and it's worked very well.