Here's my take on what's going to see more play under the new codex:
In:
- Special Characters. Some are better than others, but all are very attractive options. As an Ultramarines player, I'm especially psyched to try out Marneus Calgar, who has finally taken his rightful place as the biggest BAMF in the Imperium. Despite his rock-hard stats, it's his God of War (whole army can choose to pass/fail Morale checks) rule that really makes him worth the 250pts.
- Combat Squads. Under the previous Codex, I wouldn't leave home without an eight-man strong Devastator squad. With the new Codex, I'm going to up the squad to full strength and split into combat squads. I can't begin to describe how useful this rule is.
- Land Raiders. The new Power of the Machine Spirit rules mean that a Land Raider can always fire a weapon, even if it moves 12". This means that Land Raiders can fulfill their assault transport role without giving up 250pts. worth of firepower to do it. This also turns out to be the only redeeming quality of the Redeemer (pun intended), which would otherwise have a much harder time finding infantry to burn.
- Librarians. For 100 points, you get a Ld10 psyker with the choice of any two psychic powers. While their slightly lowered stats prevent them from becoming top-tier close combat monsters like in previous editions, they're now much more affordable in a utility role, especially with the wide variety of new, useful powers now available (Force Dome and the deep strike one in particular).
- Mechanized Infantry. Rhinos are cheaper, and Razorbacks are now less useless. Combine that with the previously mentioned Land Raiders as well as plastic Drop Pods and you have yourself a recipe for lots of mobility. GW seems to be promoting the idea of mech inf. a lot in White Dwarf as of late (see: December issue, Tale of Four Gamers - almost every infantry unit in each army has a transport). I would never accuse GW of trying to sell more product by emphasizing a $30 transport for every infantry unit - that's for the conspiracy theorists. I'm just pointing it out. Besides, mechanized infantry is supposed to be better anyways.
- Scout Bikers. Fast and cheap (20pts)? Check. Rapid fire grenade launchers? Check. A teleport homer that works on all deep strikers, not just Termies? Check. Booby traps? Check. These guys are tactical linchpins.
Out:
- Scouts. They actually have the Scout rule now, and they're definitely more versatile, aaand a full squad is cheaper now ... but I'm still not sure if it's worth the downgraded BS of 3. Sniper rifles took an especially big hit (4+ to hit ... it was a 2+ not so many months ago).
- Extra Armor. The recent trend of upping Extra Armor from 5 to 15 pts continues. My assault cannon Dreadnought with extra armor just went from 110pts to 130pts ... I think I'll pass on the extra armor now, thanks. On the plus side, most vehicles are slightly cheaper now, so if you forgo the extra armor you'll save a few points.
- Terminator Assault Cannons. First, they knocked the Rending special rule down a peg. Then, they made cyclone missile launchers Heavy 2 instead of Heavy 1. This combination means that assault cannons are no longer the default choice for every Terminator squad, ever. They're more on par with the Cyclone now.