At the moment it seems the only thing to spread grass is more grass. Since the shrub blocks share the same conditions as grass it would be nice that upon planting them it can create a grass tile as well, which will then spread. That way grass can be spread at least somewhat manually without having to create extremely complex methods to move it.
I would say yes, but you can easily do that yourself, take the code that allows grass to spread and add it to the flower code. It may be simple for the game, but some people (Like me) don't want it in their game.
That no-brain piggies thing explains a lot.
1-Explains why they are so morrons
2-Explains why they come to us when we kill them
3-Explains where do zombie pigmen come from
4-Doesn't explain why this guy has sig'd me