I think the stratagems are great, and they finally accomplish giving the Deathwing some better use and value.
Tactical Doctrine and Bolter Drill means that now you can deepstrike 5 barebone terminators for 165 points, fire 40 shots at 2CP, in turn 2, and have them wreck squads better than ever before, at no extra cost than what we had to pay before the book.
Combining the Pennant of Remembrance on a Deathwing Ancient, with either Transhuman Physiology (when whoever is hitting you has S6 or more), or Stand Firm (when whoever hits you has S5 or lower), will make any terminator a LOT more durable. In melee combat you can even combine this with Fortress of Shields, and make them only get injured on a 5+ at best, then save everything with a 2+ save, invul save, and then even a 5+ Feel no Pain.
If you want to go hunt for hordes, even 5 knights when paired the Ancient and 1 CP for Outnumbered But Never Outmatched, on a charge, will be hitting dishing out 26 hits. And if you go hunting for monsters, you can give the Ancient the Lay Low the Mighty warlord trait and get FULL to wound rerrolls on 21 attacks on a 5 man squad.
I am liking what I see. The only issue is that it is CP heavy and, due to limitations on stratagems, you are looking at abilities that work best on armies that include that ONE good unit of whatever it is you plan on bringing. Multiple units can spread the enemy attacks, but you will still only be able to play your deadly combo on one.
Now, I do think it will be good to try including 5 Deathwing Terminators, 10 Deathwing Knights, and the Ancient with the Pennant of Remembrance.
You can add a Ravenwing Biker squad that can move into position with Full Throttle (1CP),
> then drop the Terminators beyond 9" to shoot (2CP),
>> drop the Knights beyond 6" with Combined Assault (2CP),
>>> and then charge in for a 6" distance (which has a 72% chance of landing even before rerolls, either by 1CP command reroll, or 1CP to give the ancient Master of Maneuver).
When overwatch comes in, you can make the unit T5 (1CP), and shrug off some shots. Once in melee, you can try it again, either making them 5+ to be wounded by S6+ attacks for 3CP, or by S5- attacks for 2CP.
Expensive... but good.