It seems odd, that already we are hearing about armies that we hadnt seen or heard from in a long time. Unless you own a Black Templar army, do we really remember what is in that codex? The same goes for the sudden return of Dark Angels. I for one don't remember them. Dark Angels back in 3rd edition were my army of choice, and I recall spending $500 one day on metal terminators to get an all Deathwing Terminator army. Now suddenly those armies are back, and very well could be back with a vengence.
When I make my army lists, I generally take into consideration a lot of common list types that I often see on the tabletop. This is all changing, and quickly. 2011 is going to be one of the best years for Warhammer 40k, as we start seeing a lot more army types hitting the fields. It has me chomping at the bit, and I can hardly sit still long enough to work on models.
Some of the quick things I am thinking? How do we deal with super cheap typhoons, or deathwing terminators. What about Black Templar Landraiders with Blessed Hulls. No lance weaponry can penetrate them. Not only that, but the rumor mill has Stormravens able to appear in any army list. If this happens, suddenly you have marines reaching your lines with extreme prejudice. Now Grey Knights are right around the corner as well.
So many new army types will be hitting the fields in a very very short time. We still haven't had enough time to adjust to the Dark Eldar, much less all this. I for one am very excited to start facing all these new army types. It feels like a new game with so many new possiblities. Bravo GW.