Cover
I have been slogging through the new 5.0 40K book and I got to the bit about cover. (BTW, if you are riding on a light rail or subway, don't try to read; all the speed up slow down can make you ill.) When they allowed a unit to shoot through an enemy unit to the unit behind, they apparently decided that they would call the rear unit in cover from the front unit. This gives the rear unit a 4+ cover save (which is unaffected by AP value). Some things stuck me about this:
1) It would seem to me that if I fielded two units with say an armor value of 6, then by putting one behind the other I would be dropping its armor value to 4+ vs shooting attacks for FREE. Whereas if I have a 3+ Space Marine, it only matters against AP3 weapons or better. Seems like the guy with weak armor gets a bigger boost and more bang for his free buck.
2) Whereas previously one tended to screen good units with throw away units, that my be reversed somewhat now. If I have a unit with a 3+ save (A) and a unit with a 6 save (B) and I put A in front, then A has a 3+ and B has a 4+. If I put A in back and B in front, I still use my 3+ save for A because it's better, but B drops from 4+ to 6. Of course if you are facing a lot of AP3 weapons, you will out that unit in the rear to give it a save. Otherwise though it seems like there is some logic in screening with your better (usually) unit or at least the better protected unit.
1) It would seem to me that if I fielded two units with say an armor value of 6, then by putting one behind the other I would be dropping its armor value to 4+ vs shooting attacks for FREE. Whereas if I have a 3+ Space Marine, it only matters against AP3 weapons or better. Seems like the guy with weak armor gets a bigger boost and more bang for his free buck.
2) Whereas previously one tended to screen good units with throw away units, that my be reversed somewhat now. If I have a unit with a 3+ save (A) and a unit with a 6 save (B) and I put A in front, then A has a 3+ and B has a 4+. If I put A in back and B in front, I still use my 3+ save for A because it's better, but B drops from 4+ to 6. Of course if you are facing a lot of AP3 weapons, you will out that unit in the rear to give it a save. Otherwise though it seems like there is some logic in screening with your better (usually) unit or at least the better protected unit.
Comments
If you are playing something like Orks, on the other hand, it's a totally viable tactic to have your Mega-Armoured Nobs (for instance) screen in front of your giant mob of Sluggas.
I haven't really studied the new Tau book yet for the armor stuff so no comment there.
I was thinking in terms of Dark Eldar though. A lot of people used to use grotesques to shield units behind them. You also see Incubi having vastly different armor than say the wytches.
Also when facing weapons that have an AP of 3 or better, it might still be relvent to Marines or Sisters. You could field some IG just as a cheap way to give a cover save to your real troops. For that matter if you somehow had a unit with a 5+i save you might then screen a unit with normal power armor. Then both would have something against those nasty Lascannons. 'Course, I have no idea how to give a whole unit a 5+i save.
For Chaos Marines, summoned daemons, Terminators, Obliterators and Thousand Sons (or anything with a Mark of Tzeentch) have them.
For Eldar, attaching a Warlock with Conceal will give a guardian squad 5+i
For Orks, attaching a Big Mek with a Kustom Force Field will give a mob of Boyz 5+i.
I'm not too familiar with Dark Eldar or Sisters, but with Tau things are a bit trickier. To do something similar would be to screen with your Stealth Suits. Enemy would have to decide between rolling to see if they CAN shoot the stealthers, or shooting the unit behind with a cover save.
...of course the downside to all this screening is double-sided. In your shooting phase, if one of your units (the screener) is in-between your shooting unit and the target, your opponent also gets a cover save from your own screening unit.
...Imagine how much that sucks for Imperial Guard. They have so many people on the table, it's near impossible to NOT grant cover saves to your own opponent.
Also new to me; I think they changed the ay you allocated hits in a squadron. Now it looks like you can and should allocate more hits than the model has wounds. I seem to recall rolling against the majority toughness and save and so forth until you had the number of wounds. Only then did you assign it to a model. If I'm remembering right, this is a big change.