BeHavior has every intention of releasing Orks and Eldar and are devoting sections of their development crew to designing them. This is the issue when allowing customers into closed alpha, some people want all the content at their fingertips immediately, there is a huge amount of development time involved. It makes perfect sense to focus on two full factions before moving on. We are getting to the point where Space Marines and Chaos have most of their primary content and Eldar should be next. If you cant handle the suspense I'd recommend refunding and waiting till the game officially releases, then youll get all your content.