The pitch texture was edited in WE6:FE - someone made the training pitch very brown and muddy and I thought it didn't look very nice. Like training in a big pile of .... ahem!
I think the pitches in WE7 are cool and don't really need much changes.
BTW, you can't "ADD" a pitch, you have to edit one already in the game, as is the case with most of the other things you can edit.