I'd say it's more that it's hard to tell what you actually want, OP. What is that tile meant to be? The title is "streetgrass" but is the tile a kerb, or a whole street, and where's the grass, where's the street? It might look good in context, but as just a tile, it doesn't read at all. What is the drawing meant to be? Even though it's "concept art", it's not doing a good job of conveying the concept, at least to people who don't already know what you're going for.
And what do you mean by "altering" the tile? Why not create new tiles according to what you need? Moreover, one tile does not make for an environment. Perhaps you should make (and show us) a bunch of outdoors tiles first, so you (and potential feedback-givers) have a sense of what your environments are like?