I'm probably the minority here, but I don't really think Orks currently fit in 40k. Not from strictly a theme perspective, but a gameplay one. For CC horde armies with shooting support, tyranids and daemons seem to be more suitable and have more diverse unit types. I guess you could argue that Ork vehicles set them apart from the other two, but Dark Eldar seem to be better at fast assaults from transports. It would be nice to see Orks finally get a monsterous creature like the squiggoth in the next codex. With the riptide and wraithknight kits, a giant squiggoth doesn't seem that far fetched. Just my 2 cents